[cc-licenses] ¿Dual licensing a bad idea?

Rob Myers rob at robmyers.org
Tue Jul 3 09:30:03 EDT 2007


Javier Candeira wrote:
> Rob Myers wrote:
>> If you are the original licensor you could dual-license under BY-SA and 
>> GPL, but that's a very bad idea.
> 
> ¿Rob, can you please expound/expand?

BY-SA and the GPL are both copyleft licenses but they are designed for 
different kinds of work and protect different kinds of use. They are 
also incompatible.

Software really shouldn't be licensed BY-SA. It doesn't protect user 
freedom as well as the GPL. In particular you don't have to provide 
modified source code. And if a user makes a BY-SA derivative of the 
software it cannot be used with GPL licensed code (such as libraries).

Art shouldn't generally be licensed GPL. There is a web site of 
GPL-licensed art, and "software art" (programs that are art) should 
definitely be licensed GPL, but media shouldn't be. Since GPL-licensed 
code can work quite happily with BY-SA licensed media assets (icons, 
sounds) and documentation, there is no real reason to separate these 
from the rest of the BY-SA commons.

I agree with Evan that more and more art is being represented as 
software (and data), but I think it is still important to distinguish 
between executable software and cultural works. Ultimately we may need 
some kind of polymorphous license that requires that you publish the 
source of your novel when it's published as a LaTeX document and 
requires that you not add a shrinkwrap license when it's published as a 
dead-tree book.

- Rob.



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