The Washington Post today is launching Who Runs Gov, a site primarily made up of a database of personalities in the United States government. If you're looking for info on your state's senator or representative, or details about a cabinet or high-ranking military official, it looks like the site could be a valuable resource.
Who Runs Gov is a wiki, powered by MindTouch. Registered users can edit the pages, but changes don't go live until the site's staffers approve the edits. Also, subjects of Who Runs Gov profile pages (or their staff) will be able to submit their own profile information for inclusion on pages about them, a fundamental difference from Wikipedia, where you're not supposed to write about yourself.
As on other wikis, users can easily check out the edits and revisions that have been made to any page.
In a quick side-by-side comparison with competitor Wikipedia, I found Who Runs Gov far more consistent and predictable, although--so far--lacking the diversity of viewpoints that makes it into many Wikipedia entries.