7.4.3 GNU General Public License

Location: http://www.gnu.org/licenses/gpl.html
Excerpts:
``Copyright (C) 1989, 1991 Free Software Foundation, Inc.
``Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.''
``GNU General Public License is intended to guarantee your freedom to share and change free software - to make sure the software is free for all its users...''
``When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish)...''
``We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software...''
``Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that re-distributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all...''
``This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License...''
``Activities other than copying, distribution and modification are not covered by this License; they are outside its scope...''
``You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License...''
``Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions...''
``If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License...''
``If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License...''
``This General Public License does not permit incorporating your program in proprietary programs.''
Comments:

Advantages of the license:

• Freedom of use. Commercial and non-commercial without notification of use is directly expressed.
  
• Mandatory attribution to the author and rights holder. This, in fact, translates into incentives for authors and their sponsors, as well.
  
• The license automatically applies to virtually all derivatives from GPL-licensed work, which ensures advantages to the public and right holders to spread.
  

1. It is limited to use in software production only.
   
2. It is based primarily on a copyright law, although acknowledges possible interference with other laws, mostly with patent laws.
   
3. It does not, in fact, distinguish between an author and his sponsor, but legally protects a rights holder, following, in this respect, copyright entirely.
   
4. The license text is copyrighted itself and thus, cannot be freely used to build other licenses upon it.