What is a 'Social Game'?

Several of the games I'm developing I think qualify as a 'social game' in that it requires you to learn and use social skills. This article provides the best explanation I've seen for this.
http://www.simplelifeforms.com/2009/01/19/what-is-a-social-game/

All games are driven by gameplay. Gameplay essentially means the basic ‘what you do’ in order to play the game. Chess is driven by strategic gameplay. The Sims is driven by character-building gameplay. Tetris is driven by speed and sorting gameplay. The common factor here is that what you are doing is testing something. Games test your skills and make you better at them, and in the process you have fun.

Social gameplay? It tests your social skills.

So a social game is one in which your social activities with other players (trading, dating, lying, flirting, charming, imploring, cajoling, whatever) actually matter. Many games have socialising (such as chat) as a part of their overall framework, but those social activities don’t really matter to how you play. World of Warcraft is a good example of this. Every player in the game has a character, but if you actually watch games in progress, 95% of the time players do not bother to play in character. There’s no test or reward for doing so.