Is this post by Ning exec Gina Bianchi the real thing or a neat story? Announcing that as of January 1 Ning will no longer support their Red Light District and the "adult" sites it contains, Bianchi offers the following reasons:

• Adult networks are unappealing to advertisers and "don't generate enough advertising to cover their costs."
• Illegal networks breed illegal networks.And bring in the authorities.
• Adult networks create work dealing with DMCA take down notices for the Ning team and it's a pain
• Supporting adult communities takes up cycles that could be used to make beautiful software.
  

Susan sez: This suggests:

• The real money in adult has always been and will always be subscriptions.
• There's room for someone like tribe to come back to life and try to make money here, isn't there?
• Ning is trying to optimize its advertising and fine tune targeting in a way that makes porn/sex redundant (maybe going more local and life stage in the ad network piece?)