Love it! I've already mentioned I have a Google Books page where I entered a few books, but this site is free from the commercialism of Google. I loved the ease of adding books and my long cherished dream of actually cataloging all of my books (two or three thousand, probably) has revived. The rating system is super-easy and the social networking aspect is cool.
I checked out the YA book groups. There is some real variety. I chuckled when I saw the Hogwarts group was the most active. That's staying power.
I couldn't resist checking out the person at the top of the list of people with my same books. Judging by her titles, she's apparently Spanish, a new or expecting mother, possibly a paramedic, interested in public speaking.
I add the Library Thing widget to my blog. Take a look!