It's a website where you can list all the books you have read, and they recommend other ones based on your preferences. You can find new authors and series, and catch up on old ones.
Anyways, they have a challenge, where you pick a number of books you want to read by the end of the year, and you try to reach it.
My goal is 50 books, and so far I've done 21.
If any of you are interested here's a link to the challenge:
Subject: GoodReads Challenge! 
Sat Jul 20, 2013 6:00 pm
