LibraryThing

At last - something that I have used before. Maybe I am not so far behind in this Web 2.0 thing as I was staring to think!
I have mostly used LibraryThing to see others reviews of books that I have read or am thinking about reading. I always find it more reliable for reviews than commercial sites since it doesn't try to sell me anything. It can be very reassuring to see that others have hated the best selling paperback that everyone swore that you would love!
I like the idea of using it for libraries, although I do see that it would only work for smaller libraries. I dread to think what it would take to put the ULs collection on there! I like anything interactive where the users can tag the books and give recommendations. I sometimes feel that there is only so much we can do when we never actually read the books. The at a glance availability feature comes in handy to. I enjoyed reading the "Social networking for bookworms" article and would recommend it to anyone who has skipped it.
The alerts feature is really useful. Not quite sure how I managed it (I think I just put in my postcode) but my LibraryThing page gives me updates on local book related events such as signings. This could be really useful for promoting the library.
Overall, I think that this is my favour tie "Thing" so far and I look forward to further developments.