Indecency is a category of explicit speech which falls short of obscenity. The Supreme Court has long since established, in cases such as Butler v. Michigan, that the government cannot ban indecency in print media. However, the right to regulate broadcast speech, based on the scarcity and pervasiveness rationales, includes a right to regulate, but not ban, indecent speech. In general, laws force the channeling of indecent speech to a time or place where it is difficult for minors to access it.
Originally, the FCC defined indecency as consisting of the so-called "seven dirty words". Later, however, it adopted a much more comprehensive definition: material which "depicts or describes sexual or excretory acts or organs." There is no exception for material with scientific, literary, artistic or political value. This is the definition of indecency which Congress has chosen to apply to the Internet. Much famous literature, the Bible included, is technically indecent. Note that banning indecency, and promoting good values, may have little to do with one another. Recently America Online decided to ban the use of the word "breast" in messages on its service--only to discover that memebers of a breast cancer survivor's group could no longer communicate with one another.