An extensive Snurblog post that examines social networking aspects of Ning and Facebook.

So in essence, Facebook’s enforced flattening of the complexities of social relationships into a binary yes/no choice dilutes the salience of its social network to the point of uselessness…And indeed, I guess, ultimately that’s what it is: a vortex, a maelstrom, a sinkhole - an insidious system for luring as many users as possible into taking up Facebook membership, for ensnaring their data trails, and for monetising their online activities.

Additional resource: Axel Bruns - Who controls the means of produsage?