I like Wikipedia. The idea that people can add and edit information is great. However, I wouldn't use it to answer a patron query. Only if other sites verified the information. We use a few wikis at our library, so I've used them a few times. What do I think? Not sure. For global use they are great. For library or personal use, maybe not. I have to use them more to see if they are really helpful. The idea is good, but I think the methods we have used previously to share information worked fine. I think, perhaps, they just seem the thing to do at the moment. But, again, I don't use them often so I could be completely wrong. I edited the 23 Things wiki on PBWiki.