www.felixcohen.co.uk

A few really good papers to read on online behaviour and participation. Nielsen pulls it all together, really; his discussion of users and lurkers is very enlightening. Basically, 1% of 'site users contribute 90% of the content, 9% contribute the rest and then 90% of your site members will actually just use the content. This is borne out by the way that, say, YouTube, Amazon and, yes, even openDemocracy are used. Go read.
On the subject of cool community and collaboration, take a look at Thinkature, which is basically a blackboard that people can collaborate on, online, in real-time. Ah, the joy of AJAX. Try it out; it's really very cool , and might score you some brownie points with the boss!
And one final bit of groovy Web 2.0 ish stuuf; the browser-based Gollum browser; great for using wikipedia.
This friday is the second London Minibar, and event for web-geeks and participation kids like myself. Uh, I would say be there or be square, but, well, I guess 'be there and be square' is more suitable!