Social Media Infographics
the distance between two people in an offline world is six degrees. In a recent Facebook study for example, the average degree of separation between two people in the network is only 4.74. When focused on one country specifically, such as the U.S., Sweden, or Italy, among others, the number of hops between two people further shrinks to 3.74.
The Global Online Perspective
Quantifying future trends in online sharing
Social demographics: who's using today's biggest networks?
Statistics of top 5 social media sites
The science of social timing
Social Media Cheat Sheet.