On Feb. 1 2004 Janet Jackson had her now famous "Wardrobe Malfunction" during The Super Bowl half time show. CBS was fined $550,000.
The incident touched off a major crusade to clean up the air waves of indecency. Politicians were on their soap boxes calling for major fines for even a curse word that some how managed to get on the air even if it was accidentally overhead in the background of some event.
Words like "bull s#*t" were removed from songs like "Money" by Pink Floyd that had been played on the radio for years. Delay systems were installed in studios every where and interviews and remote broadcasts had to be pre-recorded so that in case there was some sort of slip up, the station and the dj would not be subject to huge fines.
This is what pretty much sent Howard Stern to satellite radio and cut the balls off of a lot of rock djs. I remember at the time Bob and Tom's Camel Toe song was becoming a big hit and then it just kind of disappeared.
Things have coming back somewhat to the way they used to be pre-nipplegate, but the incident and the aftermath fueled by overreacting do-good politicians who wanted "to clean up the airwaves" was a blow to rock radio. There are a lot of things you just can't get away with anymore.
I still can't see how something an R&B pop singer did on tv turned out to have such an impact on rock radio.. Go Figure.