I also posted this at another site to perhaps shed some light on the subject. It came about from using another person's copyrighted song (music and / or lyrics) in a video and posting same.
Here's the gist of the subject matter:
Copyrights, Patents, Trademarks and InfringementInitially only covering books, copyright law was revised in the 19th century to include maps, charts, engravings, prints, musical compositions, dramatic works, photographs, paintings, drawings and sculptures. In the 20th century copyright was expanded to cover motion pictures, computer programs, sound recordings, choreography and architectural works.
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Duration of Copyright Protection
# Musicians and conductors are given copyright protection automatically after their work has been made available for public consumption. A song produced for personal or noncommercial purposes can be protected for up to 70 years after the creator's death with an approved copyright application. Recording labels and musicians can protect work for hire or commercial music for up to 95 years by applying for copyrights. Writers, movie producers and web designers must request permission to reproduce music from copyright holders unless they use public domain music. Public domain music is anything created before 1923 that has not been protected in perpetuity by its owners and descendants.
Read more: Copyright Laws in Music | eHow.com
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Copyrights vs. Patents
# Patents protect technological creations. Copyrights protect works of authorship, generally of an artistic nature. Sometimes it is difficult to determine whether a particular work is a work of technology or a work of authorship--computer programs are an obvious example. U.S. copyright law, along with the copyright law of most other nations, protects computer programs under copyright.
Read more: What Are Copyright Laws Used to Protect? | eHow.com
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Copyrights do not protect designs or logos intended to distinguish among products or producers, because these are protected under trademark law.
Read more: What Are Copyright Laws Used to Protect? | eHow.com
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Examples of copyright infringement include downloading music using file-sharing technology, creating and publicly displaying a work of "fan fiction," or selling a burned music CD or DVD. Any of these activities can be performed without penalty as long as the prior permission of the copyright holder is secured.
Read more: What Are Copyright Laws Used to Protect? | eHow.com
http://www.ehow.com/about_5375515_copyright-laws-used-protect.html#ixzz17HLRmNNF