Stumbled upon Keycontent.org. It’s free to join and then you can add your 2 cents to the content. If you to practice working with a wiki, this might be the place to start. It’s a wiki and a blog with a mission similar to this blog:
Our mission is to provide a place where expert content developers, technical communicators, information architects, and web designers can come and express their views about the profession. . . created for and by professionals who want to keep up with the important issues in the transformation of technical communication.
The site includes articles as well, including some “reprints” from the Carolina Communique, the online newsletter of the Carolina STC Chapter, which is also a wiki disguised as a Web site (or vice versa).