The words Copyleft All Wrongs Reserved was used in Dr.Dobbs Journal of May 1976. The magazine carried Li-Chen Wang's Palo Alto Tiny BASIC for the Intel 8080 microprocessor. There was the title, author's name and date with @COPYLEFT ALL WRONGS RESERVED. The copyleft symbol which is the reversed c in a full circle is copyright symbol mirrored but has no legal meaning. Under fair use the copyleft license may be superseded, like regular copyrights. Roger Rauskolb, modified and improved Li-Chen Wang's program and this was published in the December 1976 issue of Interface Age magazine. Roger added his name and preserved the COPYLEFT Notice. The Emacs General Public License of Richard Stallman was the first copyleft license which later evolved into the GNU General Public License. The Copyleft All Wrongs Reserved label was not yet there. The term "kopyleft" with the notation "All Rites Reversed" was also in use in the early 1970s.
Copyleft All Wrongs Reserved could be defined as a copyright licensing scheme in which an author surrenders some but not all rights under Copyright Law. Copyleft allows an author to impose some of the copyright restrictions on those who want to engage in activities that would otherwise be considered copyright infringement. Copyleft All Wrongs Reserved expresses the practice of using copyright law to remove restrictions on distributing copies and modified versions of a work for others and stipulates or makes a precondition/proviso that the same freedoms be preserved in modified versions.
Copyleft is a form of licensing and may be used to modify
copyrights particularly for works such as computer software. Copyleft protects the freedom
of others to use copyrighted works as if there were no copyright law at all.
Copyleft licenses are also known as viral or reciprocal licenses because under copyleft, copyright infringement may be avoided if the potential infringer perpetuates the same copyleft scheme.
An author may, through a copyleft licensing scheme, give
permission to reproduce, adapt or distribute the work as long as any resulting copies or
adaptations are also bound by the same copyleft licensing scheme. A widely used and
originating copyleft license is the GNU General Public License. Other examples are
licenses available through Creative Commons.
The term "copyleft" was originally a noun, meaning the copyright license terms of the GNU General Public License originated by Richard Stallman as part of the Free Software Foundation's work.
Copyleft gives each person possessing a copy of the work the same freedoms as the author:
to use and study the work,
to copy and share the work with others,
to modify the work, and
to distribute modified and therefore derivative works.
But these freedoms do not ensure that a derivative work will be distributed under the same liberal terms. In order for the work to be truly copyleft, the license has to ensure that the author of a derived work can only distribute such works under the same or equivalent license.
Copyleft licenses make creative use of relevant rules and laws. By submitting the copyright of their contributions under a copyleft license, they deliberately give up some of the rights that normally follow from copyright.
Copyleft licenses vary from one country to another, and may also be granted in terms that vary from country to country. In some countries it is acceptable to sell a software product without warranty. The extent of such warranties are specified in most European copyleft licenses.
Copyleft is a feature of most free software licenses. Many free software licenses are not copyleft licenses because they do not require the licensee to distribute derivative works under the same license.
Copyleft licenses are sometimes referred to as viral copyright licenses, because any works derived from a copyleft work must themselves be copyleft when distributed.