[curt]

From what I've read Groupon makes a fortune. The others like LinkedIn are trying to convert their user base into a revenue stream without driving the users away.

The problem with many web 2.0 companies is that they don't have a clear revenue stream.

[tnorthcutt]

Groupon does not make a profit: http://www.geekosystem.com/groupon-ipo/

[curt]

Wow, I read something a year ago saying they were making $30 million that year. They must have crazy expanded.