For those who go into the business of distributing {\em modified\\}

versions of GPL'd software, the burden is a bit higher, but not by

much. The glib answer is that by releasing the whole product as Free

Software, it is always easy to comply with the GPL. However,

admittedly to the dismay of FSF, many modern and complex software

systems are built using both proprietary and GPL'd components that are

not legally derivative works of each other. Sometimes, it is easier simply to

improve existing GPL'd application than to start from scratch. In

exchange for that benefit, the license requires that the modifier give

back to the commons that made the work easier in the first place. It is a

reasonable trade-off and a way to help build a better world while also

making a profit.

Note that FSF does provide services to assist companies who need

assistance in complying with the GPL. You can contact FSF's GPL

Compliance Labs at $<$compliance@fsf.org$>$.

If you are particularly interested in matters of GPL compliance, we

recommend the second course in this series, {\em GPL Compliance Case

  Studies and Legal Ethics in Free Software Licensing\/}, in which we

discuss some real GPL violation cases that FSF has worked to resolve.

Consideration of such cases can help give insight on how to handle GPL

compliance in new situations.

\appendix

\begin{center}

{\parindent 0in

Version 2, June 1991

Copyright \copyright\ 1989, 1991 Free Software Foundation, Inc.

\bigskip

59 Temple Place - Suite 330, Boston, MA  02111-1307, USA

\bigskip

Everyone is permitted to copy and distribute verbatim copies

of this license document, but changing it is not allowed.

}

\end{center}

\begin{center}

{\bf\large Preamble}

\end{center}

you use may be called something other than {\tt show w} and {\tt show c};

they could even be mouse-clicks or menu items---whatever suits your

program.

You should also get your employer (if you work as a programmer) or your

school, if any, to sign a ``copyright disclaimer'' for the program, if

necessary. Here is a sample; alter the names:

\begin{quote}

Yoyodyne, Inc., hereby disclaims all copyright interest in the program \\

`Gnomovision' (which makes passes at compilers) written by James Hacker. \\

signature of Ty Coon, 1 April 1989 \\

Ty Coon, President of Vice

\end{quote}

This General Public License does not permit incorporating your program

into proprietary programs. If your program is a subroutine library, you

may consider it more useful to permit linking proprietary applications

with the library. If this is what you want to do, use the GNU Library

General Public License instead of this License.

\begin{center}

{\parindent 0in

Version 2.1, February 1999

Copyright \copyright\ 1991, 1999 Free Software Foundation, Inc.

\bigskip

59 Temple Place - Suite 330, Boston, MA  02111-1307, USA

\bigskip

Everyone is permitted to copy and distribute verbatim copies

of this license document, but changing it is not allowed.

\bigskip

[This is the first released version of the Lesser GPL. It also counts

 as the successor of the GNU Library Public License version 2, hence

 the version number 2.1.]

}

This library is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public

License for more details.

You should have received a copy of the GNU Lesser General Public License

along with this library; if not, write to the Free Software Foundation,

Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

\end{quote}

Also add information on how to contact you by electronic and paper mail.

You should also get your employer (if you work as a programmer) or your

school, if any, to sign a ``copyright disclaimer'' for the library, if

necessary. Here is a sample; alter the names:

\begin{quote}

Yoyodyne, Inc., hereby disclaims all copyright interest in the program \\

`Gnomovision' (which makes passes at compilers) written by James Hacker. \\

signature of Ty Coon, 1 April 1990 \\

Ty Coon, President of Vice

\end{quote}

\begin{center}

{\parindent 0in

Version 1, March 2002

Copyright \copyright\ 2002 Affero, Inc.

\bigskip

510 Third Street - Suite 225, San Francisco, CA 94107, USA

\bigskip

This license is a modified version of the GNU General Public License

copyright (C) 1989, 1991 Free Software Foundation, Inc. made with

their permission. Section 2(d) has been added to cover use of software

over a computer network.

Everyone is permitted to copy and distribute verbatim copies

of this license document, but changing it is not allowed.

}

\end{center}