As a reader, would I find a rating system helpful in choosing books? Would it provide the right information I would need to make a decision about a book? If a system was put into place, who would be responsible for rating the books? Would it delay books hitting the shelves, or virtual shelves? How would the ratings be defined? Could this lead to censorship and regulation of what is available to readers?
Doesn't the publishing industry already address that issue? There are children's books, Young Adult, and Adult categories as a general guide.
Here are the basic ratings for movies:
G (General audiences) - Nothing adult themed, no cursing, no sex, no violence, no nudity.
PG (Parental Guidance Suggested) - There may be some breif nudity, profanity, and violence. No drug use.
PG13 (Parents Strongly Cautioned. Some Material May be Inappropriate for Children Under Age 13) - More than brief nudity, but not sexually oriented. Depictions of violence, but not realistic, extreme, or persistent. Single use of sexually-derived expletive. May depict drug use.
R (Restricted. Children Under 17 Require Accompanying Parent or Adult Guardian) - Adult themes. Adult activity. Hard language. Intense or persistent violence. Sexually-oriented nudity. Drug abuse.
NC17 (No One 17 and Under Admitted) - Appropriate only for adult audience. Can be based on violence, sex, abberational behavior, drug abuse, or any other element that most parents consider too strong.
I'm not sure a rating system like the one above would be helpful to me as a reader. It seems too general. I don't think a rating would tell me what I really want to know before picking up a book. For example, I don't like violence against women, children, or other vulnerable people, but a fistfight or shootout between a good guy and a bad guy is okay. It's not the level of gore for me either, so much as the level of cruelty inflicted on the helpless. (In fact, it doesn't even have to be physical violence to bother me. It could be mental or emotional abuse.) So a PG13 or R rating wouldn't necessarily help me identify those particular books I might want to avoid, and it could keep me from reading a book I would enjoy.
What about smooching and stuff?Readers view sexual content in books differently. Some don't want any sexual activity--not even a suggestion. Some are okay with sexual activity, but they only want it to be between married couples. Some are just fine with explicit sex scenes, but they aren't into alternative lifestyles. Some readers are cool with whatever.
Judging a book by its cover is okay!Heat levels are often apparent by the cover and seem more helpful than a rating, in my opinion. Blind-folds, handcuffs, and three people on the cover are good signs you might be in for a wilder read. A book with a couple partially undressed in bed is very likely to have steamy love scenes. A Regency with everyone fully dressed in traditional clothing (or an innocent-looking object on the cover) is probably a sweet read with nothing more than a kiss and a romantic declaration at the end.
Certain publishing Imprints and Lines can also tell you what to expect, such as Ellora's Cave. EC has anywhere from Cotillion Traditional Regency Romance to very hot. If a publisher doesn't have different lines that gives an idea of what to expect, there are always search categories on Amazon, Barnes & Noble, Smashwords, etc.