Maybe you have been noticing in the past few months that WoWiki has been featuring more and more ads, which in some cases have become quite obtrusive on the reading experience there. The obnoxious kind that play videos that eat up memory and CPU, and the kind that abruptly stretch out or otherwise cover up the stuff you want to look at. You know, the stuff that's not ads. Finally Wikia forced them to take on a really ugly skin, apparently, which, while not being completely unreadable, looked awful.
So they migrated all the pages over to a new site WoWpedia.org, which is hosted by Curse and has no ads. It's exact same information, it works, but far less annoying to read. So let's all edit that instead. Also, their layout is just a little better than the old one which is nice. They really want people to radically update WoWpedia.org because WoWwiki had a lot of outdated or incomplete information (which is just a necessary consequence of the fact that all editing of individual pages was by nature ad hoc). Particularly they point out class pages and specs.
You can also migrate your user account page by following the directions here. Then you can edit away. Look here to read the welcome to WoWpedia.com, for more information about it.