WhatIsaWiki
A <I>wiki</I> is a collection of interlinked web pages, each of which can be visited and edited by anyone. You can even edit this page: just click "Edit text of this page" above or below.
So it's a collaborative website, constantly expanding as new people add pages about their interests, comment on old pages, et cetera. So, join in!
Maybe you want to know
*What is a Wiki for?
*Why on Earth would I want to contribute to a wiki?
*Who is responsible for these pages?