There is a website that thinks I look like the illegitimate lovechild of Neil Diamond and Tony Danza. MyHeritage.com uses professional face-recognition technology to compare your picture with a huge database of celebrity mugs. In seconds it'll tell you which washed-up actors and musicians you most resemble. It's free too, this web-based mockery service. Step right up and get your fifteen minutes of fame by proxy.

Another website, Riya.com, adds the same type of functionality to a photo-sharing site. Like Flickr.com, Riya lets you upload your pictures into albums, share them, search other public photos, etc.-but, unlike Flickr.com, you can also spend a few hours training it to recognize your friends' faces. You'll never have to tag your photos again-send it a photo of your friend Nick Lopez and Riya labels it 'Nick Lopez.' Presto.

These are just two examples of face recognition technology's transition into the public sphere (It's also making its debut on cell phones in Japan and in a new line of photo scanners by Kodak). Technology that used to be strictly the domain of governments and law-enforcement is now available to everyone and, surprisingly, we've eagerly embraced the debutante. Two million people tried MyHeritage's celebrity-matching service in its first two months, and Riya's users have already uploaded more than 7 million photos since it launched on March 21. "As a photo site, we have exceeded the initial growth rate of Flickr," CEO Munjal Shah told ZdNet.

Why is this surprising? Because traditionally, face recognition is guaranteed to get reporters and privacy activists partying like it's 1984. Here's a taste: In 2001, USA Today wrote that face recognition "has raised concerns about the rise of Orwellian safeguards against crime." A year later, The Los Angeles Times ran the headline "Big Brother Finds Ally in Once-Wary High Tech".

But as a commercial product, face recognition seems less threatening. Articles on Riya inevitably mention "privacy concerns", but these tend to be passing references in breathless eulogies celebrating the death of manual tagging. After all, although conspiracy theorists will still accuse Riya and MyHeritage.com of being in league with Interpol, all the data is public and is submitted by your friends-people who probably like you. How scary is that?

Actually, it's pretty scary indeed.

Compare it to government face-recognition. Since 9/11, evidence has repeatedly shown that this technology is ineffective as a surveillance tool. In 2003, Tampa Bay scrapped a project to monitor its entertainment district via face-recognition because it hadn't led to a single arrest in two years. Boston's Logan International Airport also dropped a system for identifying terrorists when it failed to match members of a test group 38 percent of the time. As a practical joke, two Japanese tourists swapped passports going through Sydney Airport-the SmartGate facial recognition system didn't even notice. In other words, there isn't much to fear.

Commercial face recognition, however, is something completely different.

Take Riya, for example. Here's how it works: First, you sign up and upload your photo collection, choosing which photos to make public or private. The more the better-Riya needs to recognize a face 30 times for any degree of accuracy. Then you train it by identifying the faces you know. While entering their names, you are encouraged to enter their email addresses because-and here's where it gets interesting - if someone else has that email address in their address book, Riya will start automatically identifying that person for them too. In other words, if someone has already trained Riya to recognize one of your friends, you won't need to train it-it will tag their faces automatically. Better yet, you can import your Gmail or Yahoo! Mail contacts and inherit the digital signatures of everyone you email, as long as they're already in the system.

Note that the more people use it, the better Riya gets at identifying people. When security software compares two pictures, a 45-degree difference in the angle of the face renders it ineffective. With Riya, the system can have dozens-even hundreds-of pictures to compare to. It's the basic principle behind the SETI@home project-because thousands of people will be constantly training the system, it will be more effective than any government supercomputer.

Now imagine that I actually do import my 398 Gmail contacts. (I will imagine this too, since I haven't had the balls to actually do it.) Suddenly, Riya might start recognizing people in the background of my photos whom I have never even met in person. If I want, I can search a cryptic email address and it will pull up all the public photos of that person-and, of course, tell me their name.

On a philosophical level, Riya turns everyone in the world with a camera and an internet connection into paparazzi. Every fabulous party picture of you is emblazoned with your name and the date and is subject to captioning. Facial recognition stretches Warhol's fifteen minutes of fame into redundancy, because everyone is famous. Always.

On a practical level, there are innumerable ways to abuse the system. Employers can see if there are any pictures of you in Tahiti on that "sick day" you took. Lovers can see what you did with ex-lovers. If you have a medical condition that you aren't public with, people may puzzle over why exactly there are so many photos of you in the hospital. Protecting your privacy will be next to impossible, because you don't need to be a member to search, and well-intentioned friends don't need permission to upload your face.

Riya is frightening precisely because no one is at the helm. Sure, governments probably know stuff about me that I wouldn't want my grandmother to find out. But at least they have the decency to keep it to themselves.