Why there aren't more Googles, redux. (Umair Haque), an alternative perspective to PG

I liked his link about the tech IPO market being dead because of the types of businesses being built not because of lack of interest from the market. Here's the link he was talking about: http://smoothspan.wordpress.com/2008/04/15/how-to-fix-ventur...

Does anyone know of any companies that they thought should have been able to IPO but couldn't?