A big home for all facts and figures around social media - because I'm fed up of trawling around for them and I'm also sure that I'm not the only one who gets asked 'how many users does Facebook have?' every hour of every day. It's not the snazziest name for a project ever. Oh well. I'm hoping that this wiki will not only include usage stats, but also behaviour and attitude stats. Social Media Statistics: Welcome to Social Media Statistics
10 Stunning (And Useful) Stats About Twitter UPDATE: Follow me at @rohitbhargava if you liked this post! Last month a social media analytics provider named Sysomos released a comprehensive report on Twitter usage. The problem with most analysis on Twitter, though, is that it is limited by the minimal amount of data that Twitter collects. So, to fill the gaps, most reports do things like guessing gender based on real names or pulling data from keywords in people's biographic information.
1. Index This compares audience composition of the site or mobile app to each platform population. The higher the index number, the more concentrated the property is in a particular demographic. As an example, if a property indexes 100 for age 18-24, that means a given visitor to it is as likely to be 18-24 as any internet user chosen at random. An index of 200 means the visitor is twice as likely to be 18-24, 50 means half as likely, and so on. twitter.com - Quantcast Audience Profile
Is 22 Tweets-Per-Day the Optimum?