Poor man's copyright
Poor man's copyright refers to the method of using registered dating by the postal service, a notary public or other highly trusted source to date intellectual property, thereby helping to establish that the material has been in one's possession since a particular time. The concept is based on the notion that, in the event that such intellectual property were to be misused by a third party, the poor-man's copyright would at least establish a legally-recognized date of possession before any proof which a third party may possess.
The PMC was originally used by authors who sent copies of their own work to themselves through the mail without opening the envelopes in the hope that it would grant them legal protection by establishing a date at which the work was created. Use of this method may not hold up in a court as it is simple for individuals to pre-send envelopes which can then be used later by placing the materials inside.