Where I come from, people share stories, information and history by painting on cave walls. Now most people use wikis. Wikis are an amazing tool that people from everywhere can contribute to a knowledge base.
What was life like before wikipedia? I often wonder about the impact of this wiki and how much people rely on it for information. The wikis I looked at spurred some ideas that, like all the other 23 Things, are going to take more time to marinate in my Neanderthal brain on how I will use it in class.
I use wikis all the time to gather information. I rely on them immensly, particulary Wikipedia. If I need to know some more about a chemical or other science topic I go right to Wikipedia. I couldn't imagine having to look some of this information up in a "book". The idea is so old school to me.