Book Ratings, Anyone?

The other day I was discussing with someone that it would be nice if books had a ratings system similar to that of TV or movies. That way, you don't crack open a book, get involved in the story, then get blindsided by something you weren't expecting. Last night I happened across this blog: The Literate Mother which happens to do that very thing. From what I gather, a group of mom's got together and created this blog, rating youth and young adult literature. Go over and check it out!