I have been using www.Goodreads.com for a few years now and have nearly 570 books reviewed, most with commentary. I just learned of www.Librarything.com and have tried (unsucessfully) to move my GR books over to their site. I’m working at it but it’s a bit of a slow process. My books range from animal husbandry, to children’s, to adult romance.
Not only do I use these books just to keep track of what I’ve read and liked but I love reading author bios, checking out other’s reviews before reading a book or series and keep track of upcoming releases. I also love that new authors, including those that are self-published, can create identities to get their books promoted for free.
If you haven’t checked out either site, now is the time. If you’d like to friend me (I love virtual friends) here are my links