Called "Groupwear", the badge has five small lights which can flash either red or green. When you meet somebody who is also wearing one, the badges communicate by infra-red beams, just like a television remote control, and swap data about their wearers. The more alike your interests, the more green lights you get - the more you disagree, the more red lights.
Rick Borovoy, a graduate student at the Media Lab at the Massachusetts Institute of Technology, who invented the "talking tags", said that they could be ideally suited for singles bars and other social situations where people are eager to talk but unsure where to start. "That's the top use that people suggest," he said yesterday.
The system forms a quick introduction to five questions that a party's host can choose. At its first outing, at an MIT Media Lab function, arriving guests filled in a computer form with multiple choice answers to questions. They included "How would you like to spend your 15 minutes of fame?" (choices: profiled in the New York Times, interviewed by Oprah Winfrey, as a hyperlink on a World-Wide Web page of the Internet) and "Who would you most like to have dinner with?" (choices: the lawyers from the OJ Simpson trial, assorted MIT gurus, or Peter Gabriel and Laurie Anderson).
The answers are coded on the badges, which then send out beams to any other badge in the vicinity to see if the answers agree.
Mr Borovoy says that much of the usefulness of the badges lies in framing interesting questions. But all is not lost even if your badges show that you disagree on all sorts of subjects. "We've had people who are good friends getting five red lights," he said.
"And with people who hadn't met each other, that often turned out to mean that you had more to talk about. People felt it was intriguing."
Mr Borovoy says that a lot of MIT's commercial sponsors have expressed interest in developing consumer versions of the badges.
But for the moment those who find social occasion problematic still have to rely on the time-tested question: "With what frequency do you visit this location?"