Todd Wilkinson was in Poland when his mother died a couple of years ago.

It was several days before the Canadian could get in touch with family and other loved ones in his native Montreal, and when he did, the outpouring of family history overwhelmed him.

"I was speaking with my Aunt who told me things about my mother I never knew. I remember thinking: why is this exchange only two way? Why can't this information be shared more centrally - like spokes on a wheel," Mr Wilkinson, 40, says.

He conceived the idea of a social network where people could share their memories of someone who had died, by uploading photographs and contributing personal reflections, which could then be compiled and distributed by the family as a video.

"Then it went further," Wilkinson goes on. "I thought: what if those whose loved one died of a particular cause - breast cancer, say - wanted to get in touch with others in a similar situation. Like the American group 'Mothers Against Drunk Driving', who all had teenage sons die in car accidents."

"They could be blogging, sharing advice. After all, death is not just about the dead. It's also about the living."

Respectance.com, the company he set up a year ago and which goes live next week, is one of a number of networking sites which are using existing technologies to target a more select audience.

"These massive networks are all fine, but you've got to ask yourself: would you want a tribute to your life on Facebook, a site used by guys to pick up girls?"

His company, which has offices in San Fransisco and Krakow, has already raised $250,000 in venture capital funding, and is due to announce another round next month, having secured the backing of a large Dutch VC group.

"The future of social networking isn't about the platform - that's already there. It's about communities that can provide their members with an identity," Nil Rooijmans, head of research and development at Ilse.nl, the largest internet company in Holland, said.

"Sites that try to be too general won't work. The clever ones are aiming to be more niche."

Diederik Martens was "on the top of a mountain in Italy", when he had the idea for Twones.com, a site which attempts to match people with similar music tastes based on the songs in their iTunes playlist.

A user uploads their entire music library, and when the site finds another profile with a given number of songs in common, the pair are put in touch.

"The idea was that you music collection says a great deal about who you are, and is potentially a great way to meet like minded people," said Mr Martens, whose site, only launched last week, has 500 users.

"Some music networks ask you to say what you like," he said, nodding to recommendation services such as last.fm. "This site, because it checks which are the 100 most played songs in your iTunes at any one time, is a more accurate reflection of your taste."

Other start ups seeking investment at Next Web, a conference on the theme of Web 2.0 in Amsterdam, were Sugarstats.com, a site which invites diabetics to share information about their sugar levels, and Wakoopa, a network whose members can see how often others are using certain pieces of software. "It's particularly popular with gamers," Wakoopa's founder Robert Gaal, 22, said.

"Like any market, social networking is maturing," Robert Schrimpff, an associate with TVM Capital, a German venture capital group, said. "There'll always be the giants, but increasingly, small, astutely run sites which put like-minded users in touch with one another will be successful."

Joost Van De Wijgerd, an internet entrepreneur who made money selling enterprise software during the dot-com boom, said: "The problem, of course, is the revenue model. You need millions of users to get end worth from a network supported by advertising. That's why I wouldn't bet my social networking site on advertising alone. It's too thin."

The point has apparently been borne in mind by Respectance.com, which will charge $1 for each funeral video downloaded.