Wikis

Everything about 2.0 is really interesting and worth knowing about and appreciating! There is so much out there in different formats - blogs, wikis, then there's rss, flickr and facebook to name a few. A person could their whole day on the Internet!
Wikis I feel are quicker to use than blogs. Anyone can participate by contributing so you do need to be careful when relying on content informtation.
Wikis offer a quick and easy way for people to add and respond with information.
Library Book groups are of course my first thought for use in libraries. I really liked the Book Lovers Wiki - 5 star review.