I've just found out about a site called BookRabbit where you can get a free book (from 30 June until they run out!) by joining and uploading a photo of your bookshelves. Simply tag 5 or more of your books and they'll select a free book for you (based on the selection of books you tagged).
I'm not 100% sure what the site's about yet but it seems to be a book discussion thingy as well as an online book retailer (no, I didn't read the small print!) and it displays your real name next to your bookshelf so if you're worried about people googling you it might not be for you. I'm not a fan of being googleable but I'm a sucker for a free book so I signed up!
Oh...and if you're a published author you can sign up as 'author' rather than 'reader' so you might get to promote your book or something (I've got no idea...not being a published author myself yet *sob*). Also, if you're a published author you can search for books by you, find out how many people have your book on their book shelf and then look at your book on their bookshelf (and see which books yours is sitting next to!). That's so cool. God I want to be published...;0)
If you're interested click the link below:
And if you know my full real name I think you can search for me and have a nose at two of my bookshelves!