wikis

I have very mixed feelings about wikis. I enjoy our IS wiki for sharing info or good websites. Wikipedia sometimes has valuable info, but what is the source and authority? Since I have encountered a number of photos and photo tricks around the Internet, I have become more and more suspicious of sources. I liked the example of the camper's group--I think a wiki for a short-term committe or library collaborative project would be helpful. Did not know we had a building project wiki, but that is a good library example. Wikibooks intrigued me, alas it supposedly is offering textbooks, and none of interest to me. Where do those geologists hide? Wikimedia commons had photos, but some of the categories I checked were nearly empty. Maybe it is not as popular a photo-hosting site.