I just did my "Collaboration on a Shoestring" session for the Illinois Online Conference, where we talked about using Web 2.0 technologies for training purposes. I'm always interested in seeing how people repurpose these technologies in interesting ways and to suit varying needs. A local restaurant, Piedmont, is using a blog as a quick, easy-to-edit, free way of updating its daily menu. (The restaurant's good, too!)
What other unusual uses are out there for blogs, wikis, and other Web 2.0 tools?