Nice infograph showing how 5% of Twitter users make up 75% of content on Twitter. That sounds about right to me and is the same across most distinct communities. What interests me is how the other 95% are probably making up most of the content somewhere else, offline or on.

A lot of this article is about the technical stuff, which is interesting, but the universal lesson for any kind of participation is "Your workers are unpaid, so make it fun"

60 minute documentary about social media affecting society. Notable because it looks at British examples, albeit mainly from a politics / democracy POV. The stuff about the football club is interesting - moving fans from supporting a club to participating in running a club by turning it into a game of sorts.