Suzan is a 50-year-old woman from Derbyshire. She is married, has a son, doesn’t drink or smoke, enjoys European travel, prefers reading George Eliot to watching films and idolises Oscar Wilde and Nick Owen. She is keen to meet friends from all over the world — though not for kicks or sex, “so pleeeeeeease leave it out! Just genuine friends and contacts”.

I’ve never met Suzan and yet I know all this. There’s more: beneath her smiling face and neat bob on the computer screen is a list of her online friends. Among them is her own son, Wez, who is in a band called 3 Storeys High. Another is John, a 49-year-old journalist from West Sussex who works from home so has trouble meeting people in real life. Olga, a Russian opera nut from Cabot, Arkansas, recently sent Suzan a picture of a babushka doll because Suzan says on her profile that she likes that sort of thing.

Olga has 43 friends, John has 80, Wez has 395. Suzan finds herself connected with all of them. Play six degrees of separation and she is linked to a cast of thousands, potentially millions, including sweet old ladies, policemen, porn stars, politicians, musicians, doctors, astrophysicists, minor celebrities and an overwhelming number of grumpy- looking teens.

That teens are hardwired to their modems comes as little surprise. But why is a cultured married middle-aged woman networking on the internet? Does it make her seedy or, even worse, pathetic? Must her life be lacking in some fundamental way? Until recently public opinion held that grown-ups who did anything other than order groceries, buy plane tickets and Boden clothes or research their children’s history homework online were socially defective. But take this example of an exchange at a dinner party I was at the other week.

Some attractive, slightly toffy thirtysomethings were tucking into fennel salad when a Cambridge-educated lawyer said: “I met a lovely woman online the other night. We messaged for a bit and it turned out she works around the corner from the office. We went for coffee yesterday. She’s a lawyer too. We’re going to the National Portrait Gallery on Sunday.”

A few months ago the immediate response to this would have been mirthful laughter followed by a chorus of: “Internet dating! Could you be any more of a loser?” Instead his sister turned to him and asked: “Does this mean she might come skiing with us in March?” Then everyone talked about something else.

He is not alone. Among hardworking long-hours-at-the-office thirtysomethings almost everyone is doing it. The internet has replaced the workplace, the bar and the party as the safe way to make friends and find romance.

Just how did socialising on the net become de rigueur? More specifically, how did we go from thinking it the last word in desperation to a report last month that two-thirds of British singles looking for love do so by switching on their computers? My internet-dater friend explains: “I moved to London after uni and, like everyone I know, work a 60-hour week. The only girls I met were colleagues, and who wants the aggro of that? You either get done for sexual harassment or you end up in a very awkward situation when you break up three months later. I’ve been dating online for a year and all I can say is: what’s the big deal? My world was small. Now it’s huge.”

In this country 3.6m people use sites such as Match.com, DatingDirect.com and loveandfriends.com. These are merely the big hitters. “I-daters” with less catholic tastes are seeking singles on an ever increasing array of niche sites such as ConservativeMatch.com (“Sweethearts not bleeding hearts”), Single FireFighters.com (“The ONLY place to meet firefighters without calling 911”) or AsexualPals.com (“Because there is so much more to life”).

Though every taste is catered for, the surge in online users (24% in five years) is introducing previously unlikely (some would say normal) people to online socialising.

The high number of new women users can take particular credit for this sea change. Their numbers are up 28% and research shows they prefer using the net to catch up with friends, share experiences, and “talk”. All this has turned the web into what its founders threatened at the dawn of its creation more than a decade ago: a 24/7 meeting point.

Sites like Friendster.com (for hipsters) or Bebo.com and Facebook.com (for schoolkids and students) fire up the young, allowing room for personal expression that the formulaic MSN instant-messaging service never did. The sites rise and fall in popularity like nightclubs, with Friendster currently on the wane and Bebo on the make.

Recently MySpace.com — now owned by News Corporation, which also owns this newspaper — has exploded in popularity and changed everything.