A Wiki is a set of articles about various topics. It is ideal for collecting and grouping knowledge together in a single location. Wikipedia is an excellent example of a Wiki that is a version of an on-line encyclopedia. Other wikis are oriented around a specific category or area of interest. Memory Alpha is another excellent example of a wiki that is specifically for the Star Trek area of interest.
Wiki's are typically a 'community contributed content' web site. Some Wiki's allow members to directly add or edit material while others (such as this wiki) have a small membership and invites mostly viewer comments for improvements and additional information.
WeeDHoPPeR's wiki includes articles of my particular interest and expertise which, broadly, includes Cooking (recipes), Music, Computers and Gadgets, Weather Station, Home Projects, Science Fact/Fiction, Software, Web and Technology.
To use a Wiki
Wiki's are typically designed to have viewers start at their home page and enter a topic related to the wiki site content into the search box. The home page of a wiki often has highlighted feature(s) and sometimes calendar relevant events.