Wiki is a kind of webpage where everyone can help out and change the contents of the page. Blinkenshell's main webpage (the one you are browsing right now) is a Wiki. Another famous Wiki is Wikipedia.
To get started, take a look at the WikiCourse/BasicIntroduction.
You do not need to create a separate wiki account if you already have a Signup account at Blinkenshell, just log in with your signup account username and password instead.
Latest changes in this wiki: RecentChanges.