Marc Andreesen has an interesting counterpoint at http://blog.pmarca.com/2007/09/the-three-kinds.html http://blog.pmarca.com/2007/09/the-three-kinds.html where

Marc Andreesen has an interesting counterpoint at http://blog.pmarca.com/2007/09/the-three-kinds.html http://blog.pmarca.com/2007/09/the-three-kinds.html where he holds up Salesforce as an example of a 'Level 3' platform. Of course, his own Ning is another.