The FamilySearch Wiki is a large, on-line library containing thousands of articles and how-tos about doing genealogical research. Because it is a wiki web site, you can add to existing articles or write new articles.
If you are new to family history research, be sure to check out Getting Started. For more experienced researchers, be sure to check out the Research Analysis section on the Getting Started link.
On the main page begin your search by typing in something that interests you into the query box. This is a quick way to learn more about where and what you are researching. For example, a query entry into the research box for "Iowa Probate Records" will explain everything from Dower Rights to Wills. There is basic information on Iowa probate records, along with information on how to find probate records in the Family History Library and catalog, in Salt Lake City.
There are helpful videos on using FamilySearch Wiki, particularly if you are interested in contributing articles. Another interesting area is the FamilySearch Wiki Community Meeting which you can attend remotely. In these meetings everything pertaining to the wiki are discussed, such as site design and technical issues.
The FamilySearch Wiki is worth exploring. You will undoubtedly learn something new by taking the time to look around on it.