The World's Largest Genealogy wiki at http://www.werelate.org/wiki/Main_Page
is hosted by WeRelate and sponsored by the Foundation for On-Line Genealogy in partnership with the Allen County Public Library. There are over 1,908,000 people on the site. That means you should find something helpful in your research at the WeRelate wiki. It is free, but you need to register to create wiki pages of your ancestors or collaborate with others. WeRelate will send you an e-mail when changes or additions are made to pages that you have placed on their wiki. If you decide to register, be sure to watch the tutorials that are offered.
Another wiki is GenWiki at http://wiki-en.genealogy.net/Main_Page/. This pertains to genealogy in German-speaking areas of the world. They have a number of areas on the web page which link to databases, regional research, forum and mailing lists. If you are researching German ancestors, it is worthwhile to check this wiki.
There are 88,441 pages on Familypedia, http://familypedia.wikia.com/wiki/Family_History_and_Genealogy_Wiki. The site has indexes to surnames, birth country, death country and birth and death decades. You can search, create and edit wiki pages.
Dick Eastman's Encyclopedia of Genealogy is a type of wiki located at Encyclopedia of Genealogy. It is a free-content encyclopedia created by readers and it is free for searching. You can contribute information free of charge. Just click on Search in the menu bar and you are off to lots of great information.
Exploring GenealogyToday.com, you will find their Family History Wiki at Family History Wiki. They offer original documents, public domain materials and photographs. There are some unusual items on this wiki, so spend some time browsing and searching.
If you use the GEDCOM feature of your genealogical software, you may be interested in the Build a Better GEDCOM Wiki, Build a BetterGEDCOM wiki. There is a discussion on the issues of GEDCOM and what researchers wish to see available in genealogical software.
For the researcher of Jewish genealogy, The Jewish Genealogy Wiki at http://www.jgene.org/wiki/index.php/Jewish_Genealogy_Wiki is a must see. You can extend the wiki by adding your own links, but must register for an account. There are site sections, such as The Holocaust, Maps, Surnames and Family Websites and Jewish Genealogy by Location.
The FamilySearch Wikis are among my favorites. Begin at http://wiki.familysearch.org/en/Main_Page and take the tour so you will know what their wiki is all about. Entering a topic or area into the search box will pop up several possibilities. Foreign countries are represented as well as our states and links to counties. Some have more information than others. They usually offer resources, timelines, historical information, links to articles, books, web pages and links for downloading books. The information is very helpful if you are planning a research trip or trying to learn about specific locations.
Wikis are on Internet for guidance and instructions, as well as the sharing of information and ideas. They are a genealogist's best friend!