Another option is to set up your own website. Hosting can be found dirt cheap, and there are several wiki packages available for free, including Media Wiki, the software that Wikipedia runs on.
The advantage of this route is your have a lot more control over your wiki, and you don't have to worry about the host imposing ads on you. Plus you have access to all the other things you normally get from domain hosting.
Disadvantages are that it costs some money and you have to set up the wiki software as well as the wiki itself. Finding a low-cost host that you can be happy with may also be easy or difficult, depending on your needs.