Campus Wikis and Wiki Authority

Case Western Reserve University’s CaseWiki caught my eye in this article. The school published a wiki that any authorized Case user may edit (visitors may leave comments). Topics include people, academics, organizations, social life (activities, bars, restaurants, theaters, etc.). It looks to be developing into an all-purpose guide to life at CWRU.
Like so many bottom-up tools, CaseWiki relies on the self-correcting power of the population contributing to it. It’s not anonymous, so there’s reputation at stake (like in the blog world). This raises a question that occurred to me during the recent NEASIS&T “Buy, Hack, or Build” conference: what is the minimum number of participants a wiki needs to be self-correcting and (I hesitate to use this word to a librarian audience) “authoritative”? It seems to me that a small number of wiki participants — say, fewer than a dozen — lends itself to groupthink too easily. Large wikis — the Wikipedia, for example — are self correcting. Where’s the threshhold between the two? A few dozen users? A few score?
Your thoughts are welcome in the comments section…