User blog comment:Dopp/Technical Update: May 17, 2011/@comment-1142365-20110523180248/@comment-10370-20110523184146

Yeah, rough ETA is that it should be ready for Wikia Labs by the middle of June. (That means every wiki that wants it will be able to turn it on themselves.) There are a bunch of small fixes that we're working on this week, and then next week we'll start working on the big feature for this release -- private messaging. If we can hammer that out quickly, then mid-June for sure.