AAA is also industry shorthand for a specific
radio genre:
Adult Album Alternative.
The stations who have this format tend to be public radio stations like WYEP in Pittsburgh, KCRW in Santa Monica or KFOG in San Francisco, WXPN in Philadelphia or WFUV in New York.
The music played on these stations is hard to describe. Someone once told me that it was "thinking-people's pop music". So, essientally it's the pop music out there that the marketing hacks at Mtv would never play. Here is a short list of some of the artists that the station I intern at is playing right now:
For more information on the format: http://www.triplearadio.com