You're right, I just added it because I couldn't think of anything else. And obviously I thought it was a network, but whatever now.
Well, of that list, only MySpace and Facebook are straight-up social networks. Reddit is a social news site, as has been mentioned, and Twitter is a micro-blogging platform before anything else. Tumblr, which someone's brought up, is a blogging platform as well. Taking that into account, Facebook > MySpace.