Public domains refer to work not covered by copyright anymore. Public domains as related to literary, artistic, broadcasting, and musical products are works for which the copyright may have expired or for which no intellectual property rights exist or the copyrights have been forfeited. Some famous examples of public domains are that of Shakespeare works and music composed by Beethoven.
Public domains refer to information and works which are available to the public and can be used by the public because there are no intellectual property rights attached. The first time the term was used in copyright was in 1710 in the UK. Ideas are not protected by copyright law, only the material expression of such ideas. Mathematical formulas fall within the scope of public domain, but algorithms can be protected by some intellectual property rights.
Any works created before copyright laws are in public domain. It should be noted that translations and adaptations don’t form part of public domains. If the copyright on a work expires the work can fall into public domain. Government works generally fall within public domains, unless the work is enacted into law.
Public domain works form an integral part of the modern knowledge base and such should be used as sources of information. One must note that although a work is in public domain, you may still not present it as your own. You may use it, adapt it and make it available, but the work cannot be called yours unless you have substantially added onto it. Many databases exist for public domains where Internet users can locate work that can be freely copied and used without the fear of copyright infringement.