Thing 10: Wikis

I guess I was surprised to hear so many libraries using wikis as a reference resource. I was always told not use wikis as a source of reference, especially when using "wikipedia". Because of this I never really used wikis before, or edited one, but it was easier than I thought it was going to be. I added a comment to the 23 things on a stick wiki, nothing important of course. I did read a comment on this wiki page that made me think, someone posed the question "what is the difference between wikis and Googledocs"? What is the difference, are they not both place for a group of people to come to edit and share information. Why do we need so many different ways to do this?