The problem with a filterable "ratings" system is who's on the committee who makes the decision? Who ultimately pays for the lawsuit when an author whose work gets mistakenly (or over-zealously) rated/categorized loses sales because his/her work has been made less visible to otherwise potential customers? Who makes the decision that borderline material is going to get less exposure than it might otherwise deserve?
A rating system works for movies because there's not thousands of different movies coming out or playing in every single theater on any given day. The MPAA's job would be a cakewalk compared to the daunting task any sort of generic (or even proprietary) literary rating committee/system would face.
A customer-based rating/tagging system might work better, but even then, the potential for perfectly innocent (or vendetta-tagged) content not showing up under an otherwise potential customer's search is not a situation that I think Amazon is ever going to want to deal with. The whole scifi/fantasy/romance/mystery/etc search criteria is already flaky enough—with complete misses and bleed-over happening. The more complicated the algorithm gets, the more titles that are going to start falling through the cracks. Finding an audience is hard enough without giving perfect strangers the ability to spot-judge your work and take it right out from under the nose of other customers that might have been perfectly willing to try it otherwise. There are no age-appropriate and/or morality-based content criteria that can be delineated cleanly enough to be assigned check-boxes that will work for everyone's searches.
And to be completely honest, I don't think there's any inherent right that people should never have to experience "unintended content" showing up in an internet search. Between descriptions, customer reviews and free samples, I think it's fairly easy to determine if it's something little Johnny (or yourself) needs to be reading.
Last edited by DiapDealer; 08-16-2012 at 12:58 PM.