Wikis

I've been using a couple of free Wiki hosting services lately. I have to say I'm pretty impressed with Jotspot.

I particularly liked their concept of a hackathon as an innovation mechanism.

I'll also be interested to see how they get on with their Jotspot Live real-time wiki interface that allows multiple users to edit the same page at the same time

A new one that is pretty simple and extremely quick to to get up and running with is Pbwiki. As they say...
"Make a free, password protected wiki as easily as a peanut butter sandwich."

And if you are after some links re Wikis this is where I started from Wikis Galore. See also the links in The Public Wiki Forums listing in the original Wiki - the
PortlandPatternRepository.

And, of course, don't forget the stonking Wikipedia, now up to 635,000+ articles in the English edition.