Of course there are other exceptions to free speech, including copyright protection, the Miller test for obscenity and regulation of advertising. There is also the FCC - Federal Communications Commission - whose sole job is to regulate the world we see on radio and TV.
Free speech is a fine, fine line. We occasionally jump back and forth on the issue, but the truth of the matter is that free speech is only free until it infringes on someone else's rights. Also:
Like all other constitutional freedoms, freedom of speech is more a contested terrain than an absolute principle...Internet and new forms of low power radio stations have increased it [freedom of speech]. What steps the courts of the United States will take to enforce freedom of speech depends somewhat on the identity of the judges appointed and the advocates for clients who appear before them.
FYI, since not everyone is from the US here, internationally, the free speech is applied this way:
1. Everyone shall have the right to hold opinions without interference.
2. Everyone shall have the right to freedom of expression; this right shall include freedom to seek, receive and impart information and ideas of all kinds, regardless of frontiers, either orally, in writing or in print, in the form of art, or through any other media of his choice.
3. The exercise of the rights provided for in paragraph 2 of this article carries with it special duties and responsibilities. It may therefore be subject to certain restrictions, but these shall only be such as are provided by law and are necessary:
(a) For respect of the rights or reputations of others;
(b) For the protection of national security or of public order (ordre public), or of public health or morals.