Wikia

Wikia is a for-profit company founded by Wikipedia's Jimmy Wales and is one of the biggest internet companies around - although you may never have heard of it. It offers users the ability to create specialized wikis about almost anything you can imagine. It is completely free and is ad supported. Rather than the company itself using a wiki for collaboration (which it may very well do), Wikia offers users the ability to simply and easily collaborate on a just about anything they want to collaborate on - TV shows, games, food...you name it. To learn more, check out this article.