Picking books for young gifted kids can be difficult. Just because a child can read at a high school level doesn't mean he or she is ready for "edgy" young adult books. So gifted parents have to either read everything before giving it to their children (Ha! Try keeping up with them!), or trust someone else--the librarian, the Caldecott committee or some other book reviewer--to determine what is or is not too frightening for your child.
Movie review sites like Movie Mom.com break down questionable movies by counting profanities, incidents of violence (cartoonish or otherwise), nudity/sex, use of alcohol or drugs. When my kids were in 4th and 5th grade and wanted to go to a PG-13 movie, I used Movie Mom frequently to make those decisions. Books did not have a similar resource until now.
Facts on Fiction is a nonprofit book review database that does for chapter books what Movie Mom does for movies. Take Dickens' A Christmas Carol, for instance. If you click here you can find FoF's evaluation of the mature subject matter in the story.
What I like best is that if you click Click Here for More Details at the bottom of the screen, it shows you exactly what the reviewer considered a reference to death, with page number and citation. That's true transparency. This is not an attempt at censorship. It's really a way for parents to search by title or reading level and then honestly evaluate if that reference to "suicide" is going to be too much for Junior or if it's just Tom Sawyer pretending he drowned so Aunt Polly won't punish him.