What is a copyright?
The copyright symbol, or copyright sign, designated by © (a circled capital letter “C”), is the symbol used in copyright notices for works other than sound recordings (which are indicated with the ℗ symbol). The use of the symbol is described in United States copyright law, and, internationally, by the Universal Copyright Convention. The C stands for copyright. Because the © symbol has long been unavailable on typewriters and ASCII-based computer systems, it has been common to approximate this symbol with the characters (C).
A copyright notice or copyright symbol is an identifier placed on copies of a work to inform the world of copyright ownership. While use of a copyright notice was once required as a condition of copyright protection, it is now optional. U.S. law no longer requires the use of a copyright notice, although it is often beneficial. Prior law did, however, contain such a requirement, and the use of a notice is still relevant to the copyright status of older works. Unlike use of the ® symbol for registered trademarks, use of the copyright notice is the responsibility of the copyright owner and does not require advance permission from, or registration with, the Copyright Office.
Use of the copyright notice may be important because it informs the public that the work is protected by copyright, identifies the copyright owner, and shows the year of first publication. If a proper notice of copyright appears on the published copy or copies to which a defendant in a copyright infringement suit had access, then a defendant’s defense based on innocent infringement is null and void. Innocent infringement occurs when the infringer did not realize that the work was protected.
For more information on use of the copyright symbol and copyright rights, please see:
What is a copyleft?
Copyleft, designated by (ɔ) (a backwards circled capital letter “C”) is a general method for making a program (or other work) free, and requiring all modified and extended versions of the program to be free as well. Free does not necessarily mean free of cost, but free as in freely available to be modified.
Copyleft is not recognized by the US government and is granted no rights under US laws. It is a convention that started from common usage. ‘Copyleft’ is a play on the word ‘copyright’ to describe the practice of using copyright law to offer the right to distribute copies and modified versions of a work and requiring that the same rights be preserved in modified versions of the work.
Copyleft can be characterized as a copyright licensing scheme in which an author surrenders some but not all rights under copyright law. Instead of allowing a work to fall completely into the public domain (where no ownership of copyright is claimed), copyleft allows an author to impose some restrictions on those who want to engage in activities that would more usually be reserved by the copyright holder. Under copyleft, derived works may be produced provided they are released under the compatible copyleft scheme.
What is the difference between copyright and copyleft?
Copyleft is a form of licensing and can be used to maintain copyright conditions for works such as computer software, documents, and art. In general, copyright law is used by an author to prohibit others from reproducing, adapting, or distributing copies of the author’s work. In contrast, under copyleft, an author may give every person who receives a copy of a work permission to reproduce, adapt or distribute it and require that any resulting copies or adaptations are also bound by the same licensing agreement.
Copyleft is often used in relation to software in the public domain. Copyleft licenses (for software) require that information necessary for reproducing and modifying the work must be made available to recipients of the executable. The source code files will usually contain a copy of the license terms and acknowledge the author(s). Copyleft type licenses are a novel use of existing copyright law to ensure a work remains freely available. The GNU General Public License, originally written by Richard Stallman, was the first copyleft license to see extensive use, and continues to dominate the licensing of copylefted software. Creative Commons, a non-profit organization founded by Lawrence Lessig, provides a similar license.
For more information on use of the copyleft symbol and its proper usage see:
Guide to Copyright and DMCA for Online Publishers – https://blogging.im/copyright-
This guide will provides comprehensive coverage of copyright and DMCA laws for bloggers (and anyone who publishes online).