User blog comment:Ohmyn0/Chat is Now in Wikia Labs/@comment-1264394-20110702195228/@comment-3030984-20110703065735

That will only put a button on the homepage though. When clicked, it will not open a new window. There is a piece of js that can do that, as it pops up here on community central. Find the code here (it will be at the bottom), copy it to your wiki's wikia.js, and then wrap nobody's code with a Blarg.