92% are connected by only four degrees of separation

This is really interesting.

http://venturebeat.com/2011/11/22/facebook-degrees-of-seperation/

The viral marketing power of social gaming has become more clear. If you can convince a friend of a friend of a friend of a friend to reshare information, “everyone” will have seen it. It’s very clear this type of marketing is very powerful. Games that incorporate social elements get a really nice low-cost guerrilla marketing advantage.