IP: The GPL and commercial development

[David Farber <farber () cis upenn edu>]

-----Original Message-----
From: Richard Stallman [mailto:rms () gnu org]
Sent: Friday, January 14, 2000 8:41 PM
To: farber () cis upenn edu

You will often hear people say that the GPL does not allow use of the
code in commercial software.  This is a subtle confusion.

The GPL does not make any distinction between commercial and
noncommercial software development.  It allows businesses to do all
the same things that individuals and schools are allowed to do.

However, the GPL does forbid use of the code in *proprietary*
(non-free) software.  The GPL does not allow adding any additional
restrictions to any program that includes the code.  So any program
that incorporates the GPL-covered code, whether it be commercial,
academic, or avocational, must be released as free software.  As a
whole, it must be released under the GPL (though you can put a more
lax GPL-compatible license such as X11 on the parts you write, if you
wish).

I think that people who say the GPL disallows commercial software are
probably saying "commercial" but actually thinking "proprietary".  But
while they may understand the GPL rightly, lumping together commercial
software and proprietary software is a grave mistake.  There is plenty
of noncommercial non-free software.  There is also commercial free
software--and we want to encourage more.

If we want to encourage people to write commercial free software,
first of all we should make sure they know it is a conceivable thing.
So let's not use terminology which implies it is impossible!


Note, the GNU Project and the Free Software Foundation are not
associated with "open source".  We are part of the Free Software
Movement, not the Open Source Movement.  For more explanaion,
see http://www.gnu.org/philosophy/free-software-for-freedom.html.