Well, I looked at many many wikis and I think I have come to a brick wall. Almost without exception, there just seemed to be too much information presented in a single place. I am reminded of a friend who went to social agency for financial help and came away with all of the wonderful brochures - too many wonderful brochures - it was just too daunting to go through them all to find the advice that would be helpful to him.
Traditionally, one of our roles as librarians has always been to guide people through the information available. I understand that wikis are an attempt to gather information about a particular topic in one area and to organize it in an accessible manner- but I still find them overwhelming rather than helpful.