Subject: Re: FSB: How to Raise money for Free Software...?
From: Richard Stallman <rms@santafe.edu>
Date: Thu, 1 Jan 1998 12:19:19 -0700

    (c) The software's licensing will revert to the GNU GPL when a specific
    gross revenue is generated (or, lacking the revenue, on a specific
    deadline date [like 2 years from inception]).

This backup deadline is absolutely crucial, so please don't put it in
parentheses.  With a reasonable backup deadline, contributors can be
confident that the software will become free.  Without it, the
software might never become free, so conscientious volunteers ought to
avoid participating.

Ghostscript development uses a method somewhat like this.  Each
version of Ghostscript becomes free a year after its first release.
In the intervening time, it is semi-free, but the printer companies
that want to use it still have to license it.