I saw wetpaint.com featured in a Wall Street Journal article a couple weeks ago and just got to play with it this past week. wetpaint.com helps regular users create wikis.
Wiki is from the Hawaiian word for quick. Wiki systems are designed so that their content can be made available in a quick and uncomplicated manner. Wikis are websites or online resources that allow anyone to add and edit content collectively - like Wikipedia (in fact, I got this information from wikipedia)
One church that's using wetpaint.com is Mars Hill Seattle. Check out mhcseattle.wetpaint.com