The Motion Picture Association of America (MPAA) is a rating service, which uses a well-known (in the United States) rating system for rating movies. Other organizations also provide rating systems or services, such as SafeSurf and SurfWatch (both PICS founding members) and the Recreational Software Advisory Council (a PICS supporting member).
The MPAA rating system has only one category, the overall rating of the movie. The RSAC rating system has three categories: nudity/sex, violence, and language.
The MPAA rating system's one category has a scale with values like "G," "PG," and so forth. RSAC's nudity/sex category uses a scale with values of "suitable for all ages," "partial nudity," and so on. RSAC's language category uses a scale with values of "some profanity," "explicit sexual references" and so on.