In 2006 my friend emailed me about this new website, LibraryThing. A little while later I was signed up for a lifetime membership and I haven’t looked back. I catalogue ALL of my books here. I particularly use it to track my reading each year and as a record of what I own. Every time I purge books from my home library I updated my LT profile to note that I don’t own that book anymore. This is incredibly helpful when I’m in a used bookstore trying to figure out if I already own a copy of something (I usually do).
I’ve tried Goodreads and a few others, but none of them work well for me. I’m on Goodreads, but I hate that I get bombed with author requests all the time. LT keeps a tight rein on that. I also wish Goodreads allowed you to do half-star ratings, but no such luck. If you’ve ever thought about switching they even have a page to help you out here.
I swear I'm not getting anything to plug LibraryThing, I just love the site and am always surprised when fellow readers haven't heard of it. They have done a great job creating a community for discussing books. I love the tagging feature, which allows you to catalogue your books however you want. In about two seconds I can see how many books I read each year since 2006. I can see what books I own, which ones are on my kindle, and what children’s books I have.
Here's my Library Thing profile. Where do you all track your reading?