We track everything these days — calories, steps, sleep habits — why not reading? I'm something of an organizational nerd (just ask sports writer Will Springstead about my color-coded lists), so I love Goodreads.
Goodreads is a combination social network and virtual bookshelf. You can connect with friends, see what they're reading and read their reviews and keep track of what you're reading the books you have.
I hate when I pick up a book, get a chapter or two in, and realize I've read it before. Or buy a book and then realize it was on my shelf after all. Now, I can check my app. Or I can scan the barcode of a book at a store to see reviews, or just remind myself to find it at the library.
I use Goodreads to keep track of books I have read, want to read, own and want to own. I have a "to-buy" list that doubles as a wish list in the holiday season. Others use their accounts to track what kinds of things they're reading, creating lists for different genres or categories they want to hit.
The site lets you set up an annual reading challenge, setting how many books you'd like to read, which is nice to keep motivating you throughout the year. You can set a goal of 20 books or of 200, it's all how you read.