Jeff Clavier and I seemed to come to very similar conclusions about Ning:

[from Software Only: The 24 Hour Laundry has closed, and is replaced by Ning]

So after being offered a large number of social media applications, we are now into the meta-framework to build social media applications. The notion is interesting: as we have come to expect that any consumer application will include some element of social networking, collaborative filtering, tagging, etc., Ning has the first shot at claiming platform status in the social phenomena by offering building consistent building blocks (though wikis could probably claim anteriority).