RIBA wiki
The Royal Institute of British Architects has its own wiki: the RIBAPedia: a "collaborative, free source of information relating to architectural research". The initiative has been led by the RIBA's Research & Development Department, funded by the Centre for Excellence in Teaching and Learning through Design.
I was unaware of this until Mel Starrs brought it to my attention, but it has apparently been around for a couple of years, though it has not so far managed to attract huge numbers of users. A page entitled Making Connections says the wiki had attracted just 74 registered users (ie: potential editors) before the start of 2008, and talks about strategies to increase its use.
One problem may be that the much more well-known Wikipedia already has a wealth of information about architecture; its list of basic architecture topics is extensive and hundreds of architects are profiled. Indeed, a Wikipedia search on the words "architectural" and "research" delivered more than 9,000 results; "architectural research" delivered 44 results. The RIBAPedia could be in danger of repeating information that is already available on Wikipedia, and, without the necessary 'wisdom of crowds', giving information that is perhaps not as reliable.
Related post: Wikis and AEC collaboration (26 March 2007)
