Richard Stallman wrote:
I don't think
> it needs to be possible to use text from manuals in a program.
> A manual is free if you can publish modified versions as manuals.
And is a text editor free if you can only publish modified versions as
text editors -- not as manuals or tetris games or news-readers or web
browsers?
You have to be free to publish modified versions of the program as
tetris games and news-readers and web browsers, since those are
different programs, but a manual is a different kind of thing
entirely. It is to much to ask that it should be feasible to
conveniently publish a modified version of the program as a manual.
The GPL, for instance, does not permit this in a way that is good
for publication of books on paper.
Others have mentioned that the GPL has been successfully used to publish
books on paper.
Regardless of that, it does permit it in a way which is good for
electronic distribution. So what could possibly be wrong with a
GFDL/GPL dual license, or a GPL-conversion clause in the GFDL? Printers
could use the GFDL, and everyone else could use the GPL. :-)