You know exactly how important it is when you search each and everything in Wikipedia.
Creating a knowledge base or community for your niche is a great way to share information.
Wiki hosting services are also sometimes referred to as Wiki farm. Wiki hosting services should enable wiki-style editable web pages.
Few things that impact your choice are features such as – cost, licensing, the presence of advertising, Alexa rank.
Other technical details include – editing, features, syntax support, storage, multi-lingual support, and wiki engine.