It looks like Fog Creek is adding a Wiki to their bug tracking product Fogbugz. How I know this? Look at Joel’s latest posting. Notice the link to the Wiki? It’s a link to a Fogbugz installation.
If the Wiki is done right, with good integration with the rest of Fogbugz, this could become a very useful feature. We used the Wiki in Trac before we switched to Fogbugz, and it certainly was nice to have.