I first joined Goodreads years ago but never really understood what use it was to me then. Recently I've started using it regularly and, as an avid reader and book geek, it's proving to be pretty good. You can read real honest reviews, get recommendations for new books based on what you like, and see what your friends are reading (great for me as I'm pretty nosy when it comes to books!). Just to point out before I go on, this post is in no way sponsored by the site, I just wanted to share how much I've been enjoying it lately! (Although if anyone wants to pay me, preferably in books, I'd be more than happy!)
One of the things I like most about it is that it lets me keep a really easy record of what I've read and what I'd like to read. I'm terrible at remembering what I've read, and therefore authors I would like to read more from. I've often found myself wandering around the library thinking 'what was that really good book...?' hoping inspiration will spring from the shelves and I'll recall what I read only a few months ago. So, for someone like me with a rather poor memory this helps to catalogue what I've read, and also allows me to add books to a 'to read' shelf if I come across something I find interesting and can look up at a later date.