From TTMF, a recommendation to a website called The gathering for justice.
The gathering is concerned with imprisonment, and particularly with imprisonment of children. It's well worth visiting in its own right, and I wish it well; it is national, focused on the USA, but its model is one which should be actively considered elsewhere.
It is also well worth visiting for a demonstration of how the social networking concept can be applied to specifics by committed groups. The usual options seem to be competing in the clamour of Bebo, Facebook, MySpace, or trying to use the more focussed (but also, thereby, more trammelled) structures of LinkedIn, 2collab, etc. I'm not knocking any of those options, they are all useful and even, in the right case, excellent, but they are not addressing the needs of specific groups like Gathering.
It also sent me back to review, in one go, all that Unreal nature has said on the subject of prisons, which was a valuable result in itself.
From Gathering I went on and explored their host platform, Ning. This is a framework virtual environment of the type that is becoming common across the web for a number of purposes, specifically designed to provide interest groups with scaffolding. Type a word, any word which matters to you, into the front page (hunger, for example) and find a range of communities. Looking through them, it's obvious that the same Darwinian pressures are at work here as in any other endeavour; some are thriving, some are not, some are still finding out; but all have the same leg up onto a global stage.