I have learned something about Wikis today. I'm trying to get my head around it, but it feels like my brain is leaking.
Are they just online website templates that you fill up with content? great potential for collaboration.
Some company is happy to host your content, much like google is happy to host your blog. Zoho, for instance, provides online free wiki software and provides free hosting. You kind of have to hope that their servers will be there forever or else you lose everything.
I guess alternatively you can serve the wiki yourself, keeping the content in your own control. Sheesh, if you go down that road, why not call it a website.