n. (context informal English) The practice of mailing a sealed, dated copy of one's work to oneself as a proof of copyright ownership, rather than registering with a copyright office.
Poor man's copyright is a 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.
In countries with no central copyright registration authority, it can be difficult for an author to prove when their work was created. The United Kingdom Patent Office says this:
"... a copy could be deposited with a bank or solicitor. Alternatively, a creator could send himself or herself a copy by special delivery post (which gives a clear date stamp on the envelope), leaving the envelope unopened on its return. A number of private companies operate unofficial registers, but it would be sensible to check carefully what you will be paying for before choosing this route.
It is important to note, that this does not prove that a work is original or created by you..."
There is no provision in US copyright law regarding any such type of protection. Poor man's copyright is therefore not a substitute for registration. According to section 408 of the U.S. Copyright Act of 1976, registration of a work with the Copyright Office is not a prerequisite for copyright protection.