Web 2.0 technologies are starting to overlap, merge and mash together. Over the last few days I have heard of two wiki applications for Facebook.
Wetpaint released their Wetpaint Wiki Whiteboard application for Facebook. Wikimono released their Facebook wiki.
I do not think I have much use for a wiki application on my Facebook profile. But, I would love to see a wiki application in the Facebook Groups. So far, I am bit underwhelmed by the groups function in Facebook. It is great that you can send a message to the whole group and use the wall and discussion board. I am not sure why there is a wall and a discussion board. I would really like the ability to add applications to the group and have applications developed for groups. A group wiki is the first thing that came to mind.