By Alexandra Berzon

Megasites such as MySpace and Facebook have hogged all the headlines, but niche social networks revolving around specific people, topics or ideas have popped up all over the Internet to cater to users looking for a little discretion or focus. Spend enough time surfing the Internet, in fact, and you might find it tough to imagine there’s anything left to network around. One startup is betting there is—and that you’ll user-generate a user-generated site.

The do-it-yourself model has become the inevitable add-on to any catchy web idea. Blogger and TypePad did it for blogs. WetPaint and Wikia did it for Wikis. Now Ning has launched a new version of its software designed to help the average Joe create a social network.“We want this to be about you creating your own world, not joining ours,” says co-founder Gina Bianchini.

But it is not entirely clear how many people might actually want to do this. “The people who like to organize other people make up a much smaller group than the people who like to participate in groups,” says analyst Rob Enderle. “It’s an interesting play.”

With $9 million in funding and the support of co-founder Marc Andreessen, who invented the modern web browser and also co-founded Netscape, the Palo Alto, California-based Ning has some weight behind it. But the company’s first stab at do-it-yourself social networking was too cumbersome and technical for novices, and Ning was slammed for not living up to the hype.

But Ms. Bianchini says throughout all that, Ning had been working on coding the latest version. Meanwhile, users built 30,000 social networks on Ning. Under the new system, users can quickly and easily create an individualized social network about any topic for free, allowing Ning to run ads. For $19.95 a month users can run their own ads, and for an additional $4.95 they can use their own domain name.

Ning says users can build a vast range of social networks—from a “draft Al Gore” public network to a private network for Texas state employees. CBS used Ning to quickly launch “Who is Keppler?”—a social networking and video sharing site built around a character who made a brief appearance on hit TV show CSI.

With back-end social networking software available for purchase, and do-it-yourself companies coming up behind Ning, analysts say that the company’s software had better be easy to use if it hopes to attract enough members to reap profits.

But there could also be a limit to how many times a person will be willing to join – or create – a new network. “There’s a lot of group think. People go to Facebook and MySpace because other people are there,” says analyst Greg Sterling.