With all the press about Social Media, I've not seem much written about using Ning sites in your social marketing campaign. The estimable Larry Brauner has a great post on the topic at:
http://online-social-networking.com/introduction-to-using-ning-sites

Here's the post:

Introduction to Using Ning Sites

Larry Brauner
June 26, 2009

I’ve written quite a few articles about the Ning family of social networking sites focusing primarily on social marketing and business networking concepts.

Caroline McCarthy writes about Ning in her The Social blog at:
http://news.cnet.com/8301-13577_3-10234883-36.html?tag=mncol;posts

Here's the post:

Ning opens up more to developers
by Caroline McCarthy
May 6, 2009

Social-network creator Ning is letting those networks get even more customized: it's unveiled Ning Apps, the company's full plunge into the developer platform craze. It goes into private beta on Thursday and will launch in full later in May.