This document discusses copyleft licensing, which allows modifications to creative works as long as those modifications are also released under the same license. It outlines some of the basics of copyleft licenses, including the copyleft clause that makes them viral, and explores the ecology of different types of licenses including non-copyleft and hybrid licenses. The document also notes some of the legal issues and cases surrounding copyleft licenses and their use and enforcement.

2. Copyleft
Andrés Guadamuz
SCRIPT Centre for Research in IP and
Technology Law
University of Edinburgh

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4. A word of caution...

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10. A word of caution...

11. Realities

12. Copyleft basics

20. Copyleft licences
Licence grant: gives users permission to use, copy,
republish, redistribute, make the work available to the
public, etc.
Copyleft clause: Most important element in the licence.
Allows modifications to the work as long as the
modifications are released with the same licence.
AKA: Viral clause (controversial), or Share-alike clause.

21. Copyleft clause
“2(b) 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.” GPL v2.

22. Licence ecology
Copyleft Non-copyleft Hybrid
•GPL
•Free •BSD •Creative
Documentation •Apache Commons
Licence •Mozilla •LGPL
•EUPL

23. Copyleft popularity
Copyleft Other Non-Copyleft Public Domain
Hancock T, Free Software
Magazine, 9/3 2008

24. Creative Commons
Copyleft Non-copyleft Publc Domain

25. Legal issues

26. Litigation
Jacobsen v Katzer 535 F. 3d 137 (Artistic License, non-
copyleft.
GPLviolations.org:
Sitecom (Landgericht Muenchen No. 21 0 6123/04)
Fortinet (Landgericht Muenchen No. 21 0 7240/05).
Caldera Sys., Inc. v. Int'l Bus. Machs. Corp (D. Utah
2003) (No. 03-CV-0294).

27. Distribution chains
Author /
Owner
Licensee / Licensee / Licensee /
Derivative User Distributor
Derivative User User Distributor
User Derivative

28. Trouble with popular works?
Author

29. Licence complexity
More than 150 OSS-certified licences.
6 types of Creative Commons licences, 2 copyleft.
Compatibility: distribution of works released under two or
three different licences.
Must create map of compatible licences.

32. Semantic web

33. Concluding...

34. a.guadamuz@ed.ac.uk
CC-BY-SA