Millions have made chat-and-page software ICQ an underground sensation. What makes this gizmo so good?

When 16-year-old Katrina Arnell (screen-named KitKat) in Idaho Falls comes home from school every day, she hangs with 30 of her closest friends. Not by gabbing on the phone or going to the mall. Instead, she trades gossip and swaps photos via ICQ (think: ”I seek you”), the underground-hit chat system that has built a massive community of 13 million users in just 19 months—and that’s now growing at the rate of one million new users every 22 days. Part of a new breed of post-pager pals, Arnell and her friends have made ICQ’s free software the No. 1 PC download at CNET’s site. Meanwhile, the ICQ site itself ( has become one of the 25 hottest home destinations on the Web, according to research company Media Metrix.

So what is ICQ, and how come you haven’t heard of it? Imagine a small window on your computer screen that details which of your friends are currently online, no matter where they are on the planet. Not only can you immediately chat with anyone who has ICQ, but you can send messages and files, swap URLs, play games, or surf the Net together. New users can find eager conversationalists by clicking on a random chat button or by searching for people with similar ages, interests, or geographic locations. The ICQ window tells you whether you’ve received any messages, and, best of all, you control who is—and who’s not—on your buddy list. Think of it as a chat program-cum-online pager with an interface even Grandpa could understand.

As a result, ICQ’s chat rooms have become malls away from the mall, part of daily life for tens of thousands of young people. For obvious reasons, the software spread like the kissing disease among students before the mainstream public caught wind of it: Who else both constantly surfs the Net and desperately seeks to socialize? It helps, too, that the company behind ICQ—Tel Aviv-based Mirabilis—has eschewed ads or even revenue and instead benefits from ”word of mouse.” The approach has paid off: America Online recently purchased the company from its founders this past June for $287 million.

If you’re wondering why AOL, which already offers buddy lists and chat rooms to over 12 million users, would invest in another, Net-wide chat system, think about the value of 13 million new online faces. The company pledges, however, that ICQ will remain entirely distinct. ”We want to keep it as a separate brand,” says AOL spokesperson Tricia Primrose. ”And it’ll help us broaden our Web strategy.”

So ICQ’s 24-hour party lines will continue to flourish—and Mirabilis says that the software is finally making its way onto the desktops of housewives, office workers, and the over-30 crowd. For Katrina Arnell and millions like her, that’s a lot of new friends to make. For the rest of us, it’s just a killer app.