Investors don't seem to be losing their appetite for social networks -- at least for the top ones. The latest funding comes from Ning, which recently raised $60 million. Apparently, the valuation is a pre-money $500 million or so.

The company has lots of pedigree. That is, the co-founders include Marc Andreessen -- who is the mastermind of Netscape -- and Gina Bianchini, who is a former Goldman Sachs Group, Inc. (NYSE: GS) investment banker. They launched Ning back in October 2004. And it was good timing.

Basically, Ning allows users to easily create their own social networks, with blogs, videos, photos and so on. It has become a melting pot of creativity.

As of now, there are more than 230,000 social networks on the platform. If things continue apace, there will be about four million social networks by 2010 on Ning.

Andreessen has said -- on various occasions -- that a startup needs to raise as much money as possible. According to his blog:

"We raised the money to enable us to keep scaling given our accelerating growth... and to make sure we have plenty of firepower to survive the oncoming nuclear winter. At current growth rates, we don't need it to get to cash flow positive, but having lived through the last crunch, it's good to be conservative with these things."

Tom Taulli is the author of various books, including The Complete M&A Handbook and The Edgar Online Guide to Decoding Financial Statements. He also operates MergerBook.com.