A Lot of people don't like the GNU GPL because of its
incompatibilities with other free software or open source software
licenses. This comes up a lot when people tries to combine a GNU GPLed
program with another program released under a different free software
or open source software license.
Take for example the KDE Project (this may be a bad example,
because the problem has been already solved, but I can't think of a
clearer one). They are developing a nice looking desktop environment
for the X Window System. This kind of things are very needed and
they are releasing all their software under the GNU GPL, which is very
nice thing to do (imho). But they made a mistake (imho). They chose
to use a widget toolkit library called Qt which at that time (1998) has released under the Troll
Tech's QPL (Qt Public License).
The QPL has this restriction (at that time, 1998); "You may copy this
version of the Qt Free Edition provided that the entire archive is
distributed unchanged and as a whole, including this notice." This is
an usual condition on software license, in the practical sense means
that you cannot change their choice of license.
Now, you must link KDE to the Qt library to be able to run the KDE
programs. The GPL obliges you to distribute everything under the GPL
terms because it has this restriction; "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."
In fact the GPL goes further on it's clause 7; " If ... conditions
are imposed on you ... that contradict the conditions of this License,
they do not excuse you from the conditions of this License. If you
cannot distribute so as to satisfy simultaneously your obligations
under this License and any other pertinent obligations, then as a
consequence you may not distribute the Program at all. ...". Ouch! we
"may not distribute the Program at all."!!!.
KDE has chosen a license (the GNU GPL) which forbids all people
from distributing their software!. Nobody (at that time) was free to
distribute KDE binaries.
The conclusion may be that the GNU GPL is in some ways a very
restrictive license. I, imho, agree with this view.
In fact. I *LIKE* GNU GPL's restrictiveness. I once heard Stallman telling how one of the GPL goals is "to forbid is forbidden".
I like the idea of giving everybody the same good things that I have
available for me. Here have this freedoms, be happy, and pass them
around. But beware of trying to take away this freedoms from anybody
else!, play fair, be nice.
Almost all the software licenses are commercial contracts which
dictates how will the goods be exchanged for money to the benefit of a
particular company.
The GNU GPL is more of a social contract which dictates how will
the software be protected from hoarders, for the benefit of the
society.
Once the software has been already written, it's *SO* easy to pass
it around!. All kinds of software programs should be a commodity
available to everybody.
Support the Free Software Foundation's GNU Project!.