Over the past five or six days, I've been deeply immersed in bibliophil.org, a fantastic website I stumbledupon last week. Since then, I've spent any number of hours stuffing it with information about the books I have read over the course of my life.
Seriously, this site is incredible. I don't think I've been this excited about a website since I started using Wikipedia years ago.
Bibliophil allows you to input books you've read with information like: the date on which you read it, whether you finished reading it, whether you own it, whether you'd like to own it, as well as a rating of one to five stars and a review. They also have a folksonomy tagging system in BETA. Then, after you have a "Library," you can sort your readings by author, date, and several other ways. You can also view your statistics to see how many books you've read, and in which years. Oh, and if you don't like always having it on the web, you can export the whole thing into an Excel file.
And, since it's a web-community, you can see what other users thought of the same book, read the reviews they wrote, and see which readers have libraries most similar to yours.
To see what it's like, check out my library, which is still a work in progress. If you like it, join and be sure to add me as a "Buddy."