If your best mate of ten years suddenly sends you an e-mail asking if you will be his friend, don't be alarmed. It doesn't mean he's insecure; he has probably just signed up for Friendster (www.friendster.com), the "online community" that has been gobbling up American teens and twentysomethings over the past few months and is fast becoming the top subject of water-cooler talk this side of the Atlantic.
Founded in March, Friendster already has more than a million users, of whom around 16,000 are based in the UK. According to Friendster spokesman Kent Lindstrom, this is growing at around 15 per cent each week.
"I think it can go really far here," says Ben Holmes, a 22-year-old Londoner who spends more than an hour a day on Friendster and has amassed 108 friends in four months. "Everyone I know who has joined has become quite obsessed with it."
Friendster describes itself as "an online community that connects people through networks of friends for dating or making new friends". When you sign up, you get a page with your picture, interests and location. But unlike traditional "lonely hearts" sites, no one gets to see it until another Friendster - someone you know in "real life" - confirms they know you.
Once you have a confirmed friend, you're in, and anyone within four degrees of separation - your friends' friends' friends' friends - can see your page and contact you, and vice versa. The system ensures that only people already in your broad social network can contact you. Your page lists your confirmed friends and their "testimonials" - anything they want the Friendster community to know about you (there's no room for fiftysomething predators masquerading as twentysomethings).
If you search among your friends' friends for new company, the site will list the ways in which you are connected. You might never have met Sam from Sussex, but there are 15 paths between you - through Bob in Bristol, who knows your flatmate from university, as well as Laura from Lambeth, whose cousin works in the same office as your ex-girlfriend. In this respect, Friendster replicates both the gossip and networks of real life.
But the key to Friendster's exploding popularity is its inversion of the online dating formula that everyone fears is about being sad and alone. According to Lindstrom "Other sites are like big singles bars. Friendster is more like a dinner party. You meet new people through the introductions of existing friends.
Sceptics in the UK are unsure how far Friendster can go in a society much less upfront about making contacts than the US. "In England, networking is a dirty word," says Lucy Aitkens, 24, who works for a website setting up a similar "online community" but for Oxford and Cambridge alumni only. "And you're not going to change a culture overnight."
If Friendster makes headway in Britain, it is likely to do so by pandering to the insecure 11-year-old in all of us, who still wants to sit on the cool table in the canteen. "I just love getting testimonials," says Holmes. "People like to hear good things about themselves. I like it when someone says I'm smart, or funny, or a good laugh." That he may have known this person all his life doesn't dull his pleasure at such formal recognition.
"I had to keep reminding my Friend-sters that, before we were Friendsters, we were friends," says Tennessee Thomas, an 18-year-old Londoner now living in Los Angeles. "Friendster seems to have taken over."