Remember all the talk about how there's no money in social networks? Well, it now seems strangely academic. LinkedIn has priced its IPO, which it announced in January, and the numbers are big. TechCrunch has the details:

The company expects proceeds from the sale of the shares of stock in the offering will be approximately $146.6 million (in total the company will be raising $274 million but some of this money goes to fees etc.)...LinkedIn's IPO should debut on the NYSE fairly soon and it will be interesting to see how the Street reacts to the offering. One factor to consider is that LinkedIn is growing revenue—the company just reported that Q1 revenue in 2011 was up 110 percent to $93.9 million. Net income increased to $2.08 million, from $1.81 million in Q1 2010. The increase in sales came from the company's hiring solutions, a paid offering which helps recruiters search for professionals and list jobs on the site.

This is, of course, part of something much larger. For years, the IPO market has been all but dead. Now successful companies that waited to go public during the depths of the recession, such as Pandora, Skullcandy, and, most recently, Yelp, are looking to take advantage of the much improved market conditions. As Burt Helm reports in this month's Inc., there's even a cupcake company, Crumbs Bake Shop, aiming for a public listing.

Part of the rush, no doubt is that valuations for tech companies are ridiculously high. As the New York Times noted last week, Renren, the Chinese social network, went public at a valuation of 86 times its revenue. That's great news for Renren's founders, but it could bode ill for other start-ups if investors sour on the company:

'I don't know about some of these valuations,' said Peter Falvey, a managing director at Morgan Keegan. 'People are getting really excited, but it could end badly at some point.'

Start-ups that miss this frothy moment may find themselves unable to go public later. Hence the mad rush to IPO.