MATURE
Titles rated M (Mature) have content that may be suitable for persons ages 17 and older. Titles in this category may contain intense violence, blood and gore, sexual content, and/or strong language.
ADULTS ONLY
Titles rated AO (Adults Only) have content that should only be played by persons 18 years and older. Titles in this category may include prolonged scenes of intense violence and/or graphic sexual content and nudity.
The two ratings are seperated by the word prolonged? Jesus...why aren't games like Manhunt AO?
Personally, I think more games should get the AO rating slapped on them. But to make the system less confusing they should change the ratings from letters to number based ratings or something to make it less confusing. (example: Teen goes to 13+, Mature goes to 17+ and AO goes to 18+)