Anyone else convinced that no one really knows what a social networking site is?

New Lease on Life for Friendster?

Among social-networking sites, Hitwise said, MySpace accounted for 80 percent of all visits, well ahead of second-place Facebook, at 7.6 percent.
YouTube overtakes MySpace:

The video sharing site has taken a 3.9% share of global internet visits a day compared with 3.35% for MySpace, according to internet analysis company Alexa.

I definitely think of YouTube as a social networking site.