(FORTUNE Magazine) – As is well known, the U.S. leads all other nations in worrying about discrimination. It has various laws barring discrimination based on race, color, sex, national origin, religion, age, handicap, sexual orientation, or affectional preference. (One of these days, we mean to learn the difference between those last two entries.) It bans discrimination in employment, housing, voting, jury service, and access to government-assisted programs. And it is plainly not through yet. Yes, friends, another variety has been discovered. Remember that Supreme Court decision about commercial free speech? The question, answered affirmatively, was whether Puerto Rico could write laws banning casino advertisements in newspapers read by the islanders. Most of the ensuing argument was about the First Amendment and assumed that the aggrieved parties were principally Puerto Rican newspapers. But one of the dissents, written by John Paul Stevens, came up with a different angle. Stevens focused on the readers of those papers, and said they were victims of -- here it comes now, folks -- ''audience discrimination.'' Will it fly? Just try naming one that didn't.