Tech Talk

At the height of evening rush hour yesterday in midtown Manhattan, an eighty-year-old steam pipe buried deep below street level burst, sending a volcanic eruption of high-pressure steam mixed with dirt and crushed concrete hurtling hundreds of feet into the skyline. As thousands of commuters hurrying to Grand Central Terminal to catch trains and subways were jolted and suddenly forced to flee in panic, the nearby thoroughfares began to fill with emergency vehicles of all descriptions. The pressure of the escaping steam was so great that it destroyed the intersection of Lexington Avenue and East 41st Street, normally one of the busiest locations in the United States, and raised a continuous cauldron of roiling gas and debris several stories in height and so loud that onlookers compared its sound to a tornado's.

The famous rail terminal was evacuated and shut down. Traffic was re-routed. Businesses closed. Commuters became pedestrians, with long walks to alternate routes home. Firefighters looked on at the churning mountain of steam with little to do but watch. Police officers cordoned off the area. Emergency medical technicians cared for the injured -- with dozens sent to local hospitals. One person died from heart failure.

Within a few hours, the city's principal provider of electric and steam power, Con Edison of New York, managed to shut down parts of Manhattan's underground system sufficiently to bring the rumbling steam to a standstill. Then the damage assessment and the investigations began. By this morning, a small army of repair personnel was hard at work trying to dig through tons of rubble to reach the source of the explosion. [see last month's story "How to See the Unseen City" for a graphical view of underground infrastructure.]

It was a frightening evening for many New Yorkers. The city's well-known mayor, Michael Bloomberg, began a press conference by reassuring the public that the incident was "not related to terrorism but rather to a fault in our infrastructure." Still, it was little comfort to those who were directly affected. A manager of a supermarket near the blast site spoke yesterday about how the situation reminded him of the September 11 attack on the city. He said he witnessed hundreds of people running through the streets in fear in the moments after the shock wave rumbled through the corridors of the neighborhood's tall buildings.

The damage to the area's infrastructure will put a strain on power delivery today, according to a morning announcement from Con Edison. The utility said: "Con Edison has asked managers of large commercial buildings to reduce their electricity use and is asking residential customers in this area not to use appliances such as washers, dryers, air conditioners and other energy-intensive equipment during peak hours of 1 pm to 6 pm and to turn off lights and televisions when not in use until the cable problems are resolved."

Early speculation on the cause of the explosion centered around a phenomenon known as "water hammer," in which cool water condenses in a closed section of pipe. When that water mixes with steam, pressure in the pipe can skyrocket. The metropolitan area was deluged with a thunderstorm yesterday, during morning rush hour.

The main health fear today comes in conflicting reports on the level of asbestos thrown into the air and onto surfaces in the mixed-use neighborhood. Officials were still attempting to measure the level of the carcinogenic substance used in the insulation of much of the city's aging subterranean power conduits.

The offices of IEEE Spectrum are located seven blocks from the site of the eruption in a high-rise building. No one on the staff of the publication was hurt by the event.

Senior Editor Jean Kumagai recounted her experience watching the emergency as follows:

"I was still at the office at the time. I heard a low rumble before I saw anything -- at first it sounded like thunder, but then it went on and on. I turned around and looked out my window, which faces northeast toward the Chrysler Building. That's when I saw the huge billows of smoke and steam drifting westward and engulfing all of the buildings nearby. I had [an] immediate sickening feeling.

"After maybe 10 or 15 minutes, the radio stations began running reports -- at first they said a power transformer had exploded, later it became a steam pipe. The main thing was that it wasn't terrorists. A huge relief, though, [but] still traumatic for those who were injured, of course."

The thoughts and good wishes of those on the staff of Spectrum go out to the families of those who were killed or injured in yesterday's tragic circumstances.

from the desk of associate editor Sandra Upson

The U.S. Food and Drug Administration recently approved two implantable devices that treat depression by transmitting electronic pulses to a nerve in the neck. Cyberonics Inc. says its two devices are 43 percent smaller than earlier model nerve stimulators and allow for easier monitoring by physicians.

As weâ''ve reported here and here, electronic methods of stimulating the brain to treat depression have historically faced bumpy approval processes. Cyberonics finally got the FDA nod to market its implant in the United States in 2005, four years after it gained conditional approval for depression therapy in the European Union and Canada. Vagus nerve stimulation therapyâ''and Cyberonicsâ''also received a devastating blow this year when Medicare decided not to cover it.

This controversial pacemaker for the brain works by having a surgeon insert an electrode into a patientâ''s neck and wrap it around a nerve. That electrode plugs into a pulse generator the size of a pocket-watch that the surgeon slides under the skin of the patientâ''s chest. Every few minutes, the pulse generatorâ''called a vagus nerve stimulatorâ''sends a buzz of current along the nerve and into the brain. Clinical trials have indicated that the treatment, which was originally used to tame epileptic seizures, is able to improve patientsâ'' moods in cases where more traditional psychiatric methods have failed. Vagus nerve stimulation therapy is not the only psychiatric treatment method vying for a slice of the antidepressant market, as Spectrum reported in March 2006.

According to Cyberonics, more than 45 000 patients have benefited from VNS therapy in the past ten years.

As nanotechnology remains a mystery to most peopleâ''what it is and what it will doâ''it generates the same kind of fear of anything that is unknown.

We are given a fairly thorough catalogue of these fears in a recent blog belonging to Government Computer News.

We get this breathless revelation â''normally benign materials can become toxic when nanosized because microscopic particles tend to react more readily with human tissues and other substances.â'' The subjunctive thought coming from the â''canâ'' sounds a bit more indicative than the science may support, but in truth we donâ''t know.

The piece makes no mention of the distinction between â''manufacturedâ'' nanomaterials like carbon nanotubes versus the nanoparticles that are produced from car tires as they drive on the road, or since mankind first mastered fire. But, presumably, the authorâ''s sole concern here is evil industry producing nanomaterials that are integrated into our everyday productsâ''like our computer mouses.

Then there is the problem of the distinction between manufactured nanoparticles that are integrated into a material matrix and â''freeâ'' nanoparticles that may exist in laboratories and manufacturing processes that are involved in integrating these nanoparticles into products.

Back in 2004 the Royal Society looked broadly and specifically at nanotechnology and its impacts.

While today the Royal Society report does not represent the latest research on the subject of nanotechnology and its toxicological issues, it at least puts the issue in some perspective that can still guide the concerned today on where the problems are. It rightly points out the above distinctions: â''manufacturedâ'' versus â''environmentalâ'' nanoparticles and nanoparticles that are confined in a â''matrixâ'' versus those that are â''freeâ'' (not in a matrix).

As alarming as the term â''nanotechnologyâ'' is for many people, there are other materials and chemicals that we know are toxic but when integrated into a final product are totally benign. But fear over these other materials has never materialized as it has with nanotechnology, which comes with an umbrella term that can represent an unknown and unbridled science.

The call for more research into the toxicological issues contained within the piece is a legitimate one, and one that has been answered by both government and industry. But these calls should be made with a modicum of understanding and a healthy restraint on hysteria.

It is from pieces like this that leads me to believe that the dark side of nanotech is not the hidden harm that it could do, but how nanotech remains in the dark for most people.

The heaviest portion of a modern soldier's gear these days might be the multiple batteries he or she has to lug around in combat. That's the word from the U.S. Director of Defense Research and Engineering (DDRE), John Young, who is offering a million dollar prize for the inventor who can come up with the most efficient Wearable Power System. The purpose of the new contest is to "provide superior technical solutions for the individual energy needs of Soldiers, Marines, Airmen and Sailors in the field," the DDRE announced on a special Web site. "We seek a wearable power system that lasts four days and reduces the weight of the battery load typically carried by those in the field."

To win the top prize (or cash grants of US $ 500 000 for second and $250 000 for third places), you have to construct the best working prototype of a vest-attachable power unit that can run for 96 hours, weigh 4 kilograms or less, and generate 20 watts on average with peak operation of up to 200 W. In the case of systems with identical mass, a secondary wearability criterion will be used, the DDRE said. Wearability is measured by the maximum thickness of the system as it protrudes from the body when attached to a garment, with the winner being the thinner.

Entrants must register applications with the DDRE by 30 November 2007 (with some nationality restrictions applicable). The competition -- which will be judged by senior-level government scientists, engineers, and military personnel -- will consist of both bench and field tests. The winning entries will be announced in autumn of next year.

The Department of Defense said in a press release that batteries are essential to the mission of individual combat personnel, who must lug around about 8 kg or more of power packs to run the radios, night vision devices, global positioning systems, and other items needed to maintain superior fighting capability.

"In many missions the batteries are heavier then the ammunition they are carrying," Dr. William S. Rees Jr., the Deputy Undersecretary of Defense for Laboratories and Basic Sciences told the CNN news service. "We'd like to reverse that ratio."

In the field-test portion of the competition, CNN reported, the top performing systems will take part in an 8-hour trial meant to mimic real life troop activities. Competitors will strap on the prototypes and "subject their power systems to periods of walking, lying prone, outdoor environmental conditions, potentially short-term cold chambers, and off-wearer operation in an airtight container."

So for all you aspiring battery-system inventors, here's your chance to demonstrate your skills at lightening the load service members will be toting into dangerous environments in the future. They could win you a million dollars.

Iâ''m not sure a worse carrying case for an iPhone can be designed than the HipCase. What makes it notable is that almost every claim made on the packaging is false.

The HipCase features a Velcro tab and cut-out center notch to provide quick, simple, one-handed iPhone pick up.

Um, no. Iâ''d be terrified to take out the phone out one-handed, and Iâ''m one of the most dexterous people I know.

Aaargh! Thereâ''s at least a 1 in 20 chance Iâ''d drop right there, not odds you want to take with a $600 device at stake.

Corner notches ensure unobstructed access to the iPhoneâ''s headset jack

... well, yes, if you donâ''t mind pushing the leather aside a bit, you can jam the headset jack inâ''with no access to the volume controls!

â'' regardless of which hip itâ''s worn on or which way itâ''s placed in the holster, thus allowing you to listen to music or take a call while keeping the iPhone safely cradled in the HipCase.

Well-placed? Unless you want access to the volume controls! Or the â''Silentâ'' switch. Or to look at the screen at all. And how exactly are you supposed to â''take a callâ'' without being able to touch the screen at all?

The HipCase came out before the iPhone, and itâ''s as if its designers didnâ''t even have a sketch to work from. They guessed wrong, and badly so. But the copywriters went ahead and wrote something so far from the truth that â''Dewey Defeats Trumanâ'' looks dead-on by comparison. I guess thatâ''s their job. And mine is to slam them for it.

This publication has been following the progress of Oscar Pistorius for two years now. Who's he?

Pistorius is a young athlete from South Africa who was born without feet and lower legs and eventually was fitted with a pair of special prosthetics that enabled him to take up running. He quickly became so good at it that he began to set records on the track for persons with disabilities. What happened next, though, was astounding. At the Paralympic Games in Athens in 2004 (held in conjunction with the Olympics), Pistorius shocked the world of track and field by posting a time of 21.97 seconds in the 200 meters -- only 2.65 seconds off the pace of the world record for able-bodied runners. And he was getting faster in subsequent competitions.

For a backgrounder on Pistorius, you can start with contributor Marlowe Hood's full-length introduction to the young phenom, "Born to Run" (one of the first exclusive features to appear in Spectrum Online). In his report, Hood notes:

A revolution in new materials, the ever-shrinking microprocessor, and the power of CAD design tools have all pushed the technology of prostheses, in the words of Massachusetts Institute of Technology engineer Hugh Herr, to the 'threshold of a new age'. The bionic man -- or at least a microprocessor-controlled bionic leg -- is already a reality. But even in the realm of passive prostheses, which by definition do not produce energy but only store and release it, recent changes have made it possible for a lower-limb amputee to run faster than ever seemed imaginable. Maybe too fast.

In an editorial in the December 2005 issue of IEEE Spectrum magazine, Editor-in-Chief Susan Hassler wondered " When Is a Disability an Advantage?".

In May of this year, we posted a Tech Talk entry that observed that: Pistorius won two gold medals in sprint events at the Paralympic World Cup in Manchester, England. His times were spectacular. His physical status, though, is what grabbed the attention of the press. He has become an overnight sensation, a cause célÿbre for the rights of the disabled, and a dilemma for authorities in the world of sports.

Now comes word that officials at the International Association of Athletic Federations (IAAF) are giving Pistorius's carbon-fiber prosthetic legs a second look in terms of competitive fairness. Pistorius took part in two track meets in the last few days and had mixed performances. In Rome on Friday, he finished second in the Golden League B-field 400 meters with a time of 46.90 seconds. And in Sheffield, England, on Sunday, he finished last (47.65) in heavy rain and was disqualified for running outside his lane against a field of elite international sprinters.

In a news item from the Associated Press today, the IAAF said it is studying high-definition film of his race in Rome to see if his prostheses served to give him an unfair advantage.

"The guy Oscar beat on Friday -- the stride length was the same, but the speed through the air was slower for the able-bodied guy," IAAF spokesman Nick Davies said. "This research makes us want to do more."

Davies told the AP the initial research also showed the way Pistorius distributed energy was virtually the opposite of the way able-bodied athletes run. Unlike able-bodied runners, Pistorius was faster at the end of the race instead of the beginning.

So the saga of Oscar Pistorius continues to play out as he seeks to qualify against all comers to compete in the 2008 Olympic Games in Beijing on behalf of his country. To do so, the young man needs to record a time of 46.3 in the 400 over the course of the next 12 months. Will he do it? Will he be allowed to do it? Stay tuned. We'll keep you posted. We've been watching this remarkable athlete for two years. And we're not about to count him out of the running after he's come so far.

At least, that's the only conclusion I can come up with. Apple produces sexy devices like the iPod and iPhone, devices that â'' for the most part â'' do things you have always wanted these devices to do. The iPod finally gave MP3 players their distinction from other audio devices, by storing 50x the music other kinds of portable audio players could, and doing it in a beautiful device with a beautiful user interface. The iPhone is the first music phone that doesn't compromise on either the music player or the phone, and gives most folks most of what they would want out of a smartphone, in a beautiful device with a beautiful user interface.

The PS3 and PSP, as well as other nice devices like the Sony Reader, seem like they should take off in the same way. Why don't they?

I've never worked at Sony. It has been a long time since I've developed a game for a Sony platform. So I don't have a store of insider knowledge about how things go with Sony. But I own all the Playstations, a PSP, a Sony Reader, I have a couple of old Minidisc players in the basement (I believe I said I was a gadget freak), and I've roamed trade show floors and tech conferences for years, so I think I have a decent enough view of why Sony fails where Apple succeeds.

Apple has chosen to make devices that improve the experience people are having with things they already deal with. Sony is making devices that also make you adopt some class of technology that you didn't have before (on the assumption that this new tech is better than what you already have). So while Apple gave you a way to take your MP3 library with you, Sony DAPs made you convert your music to their ATRAC format, and put it on their MemoryStick or Minidisc media. Not that ATRAC, MemorySticks, or Minidiscs are bad, but no one had them, and thus no reason to have devices that use them.

No one has a plethora of Blu-Ray discs hanging around, in need of a player, so the fact that the PS3 plays Blu-Ray discs is nice, but not urgently so. No one had a pile of UMD movie discs hanging around, saying to themselves, "If only I had a portable player for these." eBooks are not such a big market that people are searching for that perfect ebook reader, even though Sony has pretty much produced one. Sony produces sexy devices, but as part of a family of formats and content, wanting you to embrace all of it, so they can get all of your dollars.

Sony's stuff is expensive, but so is Apple's. That's not the reason for lukewarm acceptance. Apple sees the potential of their products from the user perspective, and delivers on it. Sony sees the potential of their products from the corporate behemoth perspective, and delivers on that, and everyone can see the difference.

it's hard not to talk about the iPhone; I'm still learning about it from the virtual airwaves and from walking around with it myself.

Here are a few gripes and grins.

Gripe: EDGE is slow. The mobile version of Google (Web and Gmail) is a godsend, but EDGE is still slow. And I'm told that in New York it's relatively great, compared to lots of other places in the country. Which leads to ...

Gripe: Wi-Fi. it works, the phone prompts you with networks to connect to, it's all good except that it sucks the life out of the battery. Fast. Which leads to ...

Gripe: I have some information about the battery and battery life. Maybe most people understand this, but I did not. When Apple says that the battery will degrade after 200-300 charges, I know from painful iPod experience they mean it. It turns out that refers to "full charge cycles." So if the battery is drained to one-fourth full, and you charge it, and the same thing happens two days later, that's 1.5 full charge cycles.

My own unscientific impression of the iPod is that it makes a difference at what point you recharge, and instead of plugging the iPhone in each night and taking from mostly full to full, as I used to do with my iPod (whose battery is completely shot), I'm trying to let it drain more.

The big gripe here is dread of the day when the iPhone has to go back to Apple for a new battery. It's one thing to be without your iPod for 3 or 4 days, but your phone?? Which leads to ...

Grin: AppleCare. Sending the phone to Apple for a new battery will cost about $80 and will happen sometime after the 1-year-warranty runs out. Getting AppleCare for the second year of ownership, which will include a new battery if and when the original one degrades sufficiently will cost about $70, and include all the other things that AppleCare will cover. Speaking of iPhone contracts ...

Grin: I met the other day with the founder of a German-Swiss start-up who finds himself often on this side of the Atlantic. We compared iPhones and I asked him about its relative uselessness outside the U.S. He first pointed out that it's an incredibly functional iPod. I was surprised he'd pay $60/month for that. He then told me that he wasn't. At the store he gave a social security number that began with 999. That was enough to fail the credit check. So he was asked if he wanted to go pre-paid for the phone service. So he has the best of both worlds. The world's greatest iPod, and in the U.S. he can use it as a phone, paying only for the minutes and text messages he uses. I also compared iPhones the other day with my chiropractor....

Grin: My chiropractor is a Mac head. He has some PCs in the office, but mostly it's a Mac network. His scheduling and billing run on the Macs. When the front desk tells a doctor that a patient has arrived, it's with iChat. Very cool. When I saw him the other day, we compared phones and phone stories. He told me he got his the first night. The grin is how. "I went to the Apple store on Fifth Avenue at 9:00 p.m.," he told me. "I figured most people would forget that it's open 24 hours." Sure enough, he walked in, bought the phone, and walked out in 10 minutes, a mere 3 hours after the hundreds of people who waited on line all day and longer. There were some fears that Apple didn't make enough phones for the launch, but it turn out they did. I had lunch today with a friend who held out for the first weekend, then on Monday walked into the Apple store and out 10 minutes later with a phone.

We can talk about the progress of iPhone hacking, but the legitimate iPhone programming going on to extend its functionality is impressive all on its own.

Grin: I'm told, though haven't seen it, that there's a remote desktop application for the iPhone already that puts you in control of your office (or home) computer from the iPhone. I can't imagine using it a lot, even with a Wi-Fi connection on the iPhone, but for grabbing that one file that you left back in the office, or sending out one key e-mail message while on vacation, it's going to be a lifesaver. (The one I heard about seems to be here, make sure you read the security warnings, but there's also this.)

Grin: Twitter on the iPhone. Twitter, you may or may not know, is a weird little system in which you send messages from your phone or your computer saying what you're doing at that very moment. "On line at Starbucks," for example, or "Enjoying a beautiful sunset atop Cathedral Peak in the Sierras" (which obviously you're not doing if you're Twittering about it). Anyway, there's a separate Twitter interface for the iPhone which, smartly, involves only going to a dedicated web page, instead of any kind of new app to go onto the phone itself. There will be tons of these.

Gripe: So where are the AIM, Yahoo Messenger, and other IM apps for the iPhone? No one seems happy with Meebo and eBuddy. Best at the moment, according to Gizmodo, is Jivetalk from Beejives. I tried it briefly with Yahoo Messenger, and it seems to work pretty well. The IMs went from desktop to phone very quickly, the other way took a bit longer. And you don't see when someone is typing, which is important in chat. (Jivetalk showed "offline" one the phone, which was confusing. On the desktop, though, looking in from a different account, I was "Available," and it's not clear how to change the status to, say, "Invisible" or "Busy." Jivetalk is, after all, in its alpha release.)

IM will surely get better quickly. You have to wonder, though, if the absence of dedicated apps at the iPhone's launch was something that AT&T insisted on. IM does, after all, cut into SMS revenue for the carrier.

Grin: Speaking of iPhone versions of stuff, I really like the way Apple thought out most of the ways things work, and tweaked desktop software for the different interface. Take the weather button, for example. On the face of it, it's nothing more than the weather widget in Dashboard. But it's formatted differently, and you can scroll through your different cities by sliding screens left and right. More importantly, it knows you're not always connected to a network. So, for example, in the subway today, I pressed the Weather button and got the message: "Cannot activate EDGE network." I was then shown the most recent weather information the phone had obtained, with a small message across the bottom, "last update 9:42 a.m." The weather Dashboard widget isn't nearly as informative (though it does show the last weather it had).

Gripe: One thing that wasn't quite as fully thought out is iCal. Now let me say, one of the biggest advantages to the iPhone for me, over a Treo or Blackberry, is having the same iCal on the phone as on the desktop. I can synch with both my home and office computers, and all three have the same information (I get the same alarms three times, one on each, for a single appointment, but that's a tiny gripe). But there's no To Do list on the iPhone (that I've found, anyway). How wrong is that? I've taken to using the otherwise not very needed "Notes" button, but the To Do list on the desktop iCal lets you set priorities, alarms, and due dates, assign items to different calendars, keep lists of completed items, and so forth. None of that, of course, exists for a mere note. You can't even, as far as I can tell, re-order your notes differently from the order in which you receive them. Hey, hackers. How about doing something really useful, like recreating the To Do pushpin on the iPhone?

Final Grin: Still and all, the iPhone is a marvel of engineering and design, and I'm still thrilled with it. I told my wife on about the second day, "I love it more than any other piece of technology I've ever loved, and I've loved me some pretty good technology in my day." I'm not exactly singing it at the top of my lungs, as David Pogue of the NY Times does in his new brilliantly over-the-top video, "IPhone: The Musical," but I'm filled with the same song in my heart and lightness of step.

As part of an ongoing campaign to work toward embracing open source models for its software resources, IBM announced yesterday that it will grant 'universal and perpetual access to certain intellectual property that might be necessary to implement more than 150 standards designed to make software interoperable'. The decision was immediately applauded by developers in the open source movement.

Calling the move the largest of its kind, the Armonk, N.Y., computer giant said lifting restrictions on its trove of patents should help facilitate compatibility between future software applications and computing devices in general, as well as foster more innovative products and services and even reduce patent infringement litigation.

"IBM is sending a message that innovation and industry growth happens in an open, collaborative atmosphere," said Bob Sutor, IBM's vice president of open source and standards. "Users will adopt new technologies if they know that they can find those technologies in a variety of interchangeable, compatible products from competing vendors. We think customers will like this added assurance for the open standards upon which they have come to depend."

The IBM announcement said the intellectual property involved in the decision centered around specifications and protocols that could be involved in industrywide standards set by groups such as the World Wide Web Consortium and the Organization for the Advancement of Structured Information Standards.

According to IBM, the move should help clarify the company's position on use of its software patents and encourage their integration into open source projects. Previously, the company noted, adopters of the intellectual property in question needed to secure royalty-free licensing deals from IBM.

The company has posted an Interoperability Specifications Pledge section on its Web site, with more information on the specifics of yesterday's decision.

In a discussion thread on the software developer community site Slashdot, users responded optimistically, if a little guarded, to news of the announcement.

"It is a big enough step for a large IT corporation such as IBM to freely open up so much of their intellectual property," a discussion participant going by the handle tutwabee said. "These standards can be used by open source applications now. That is what really matters when it comes to open source and this issue."

And a responder posting under the online name petrus4 noted (in part): "They're still going to want to make money, of course ... but they're smart enough to realise that a company doesn't really control either half of the supply and demand equation. The consumer declares their demand, and a company that wants to make money and last a long time supplies that demand, rather than trying to change or control what the consumer's demand is."

Naturally, it will take quite a while to understand how much impact yesterday's decision will have on software interoperability standards going forward. However, it's not too early to believe that greater cooperation in the field is a good thing in the long run. This is a step IBM should be commended for taking.

Web statistics are getting a makeover. Yesterday, Nielsen//NetRatings, a leading provider of Internet stats, announced it will switch from primarily basing Web site usage metrics on the traditional page view to two new units of measure, total minutes and total sessions. The online research firm said that the new yardsticks more efficiently describe user activity on the Net in today's environment in which people are increasingly viewing material that no longer fits the description of a typical Web page, such as messaging, videos, and multimedia. The move could dramatically alter the landscape of online advertising.

The firm that pioneered the television ratings system said in its announcement that, while Rich Internet Application (RIA) technologies such as Ajax and streaming media are enhancing the consumer experience via a phenomenon called Web 2.0 (think of YouTube), they pose challenges to Internet audience measurement. Ajax refreshes content without reloading entire pages and streaming provides dynamically changing content within a single page or a media player. While a page view metric under-credits such engagement, Nielsen//NetRatings said, the total minutes metric provides a common denominator for user behavior that is independent of site design.

"Total minutes is the best engagement metric in this initial stage of Web 2.0 development, not only because it ensures fair measurement of Web sites using RIA and streaming media, but also of Web environments that have never been well-served by the page view, such as online gaming and Internet applications," said Scott Ross, director of product marketing for the NetView service from Nielsen//NetRatings.

The Oldsmar, Fla., firm cited the example of the discrepancy in usage metrics between the social networking sites MySpace and YouTube, in which the time spent ratio is 3.6 to 1.0, but the ratio of page views is much larger, at 10.4 to 1.0. YouTube visitors spend more time per page than MySpace, because they are primarily watching videos, requiring fewer page refreshes. While MySpace may be able to serve more ads because of its number of page refreshes, the time-spent ratio is an important comparison of audience engagement on the two sites, according to Nielsen//NetRatings.

The firm then reorganized its list of the leading properties on the Web by total minutes and found that the ranks of the Top Ten brands had slightly changed. As of May, statistics measured by minutes showed that AOL Media Network, Yahoo!, and MSN/Windows Live led the standings. These global properties were followed by Fox Interactive Media, Google, eBay, Microsoft, EA Electronic Arts Online, Apple, and YouTube.

As the Web changes, with new functionality seeming to spring up every year, look for further changes in the ways research analysts measure its usage. It's another sign of the times.