By Jeanne Mayeux
Copyright protection does not extend to any idea, procedure, process, slogan, principle, fact or discovery. Later works that merely happen to be very similar (or even identical) to earlier works do not infringe if they were, in fact, independently created.
You can’t sell or distribute, for example, libelous email messages. Also, of course, works that are obscene or invade another's rights of privacy or publicity are not publishable just because they happen to be covered by copyright.