You have to think growth for a vertical like this is not sustainable. People have been asking if Facebook's 15 minutes is up.

Quoted: ...there seems to be a 9.3% decline in their unique visitors from 33.75 million in August 2007 to 30.6 million in September 2007. Even their page views are down 3.8% from August 2007. (See chart.) The only company with worse performance: Classmates.com which has filed to go public. Its unique visitors tanked 19.8%