“It would be hard to overstate the contribution of Richard
Stallman to the digital world. The founding of the GNU project and
the creation of the GNU General Public License laid the foundations
for a wide range of free software that permeates computing from
smartphones to supercomputers. Free software has also directly
inspired like-minded movements based around sharing, such as open
access and open content (Wikipedia, notably).
At the heart of everything Stallman does lies a desire to
promote freedom, specifically the freedom of the software user, by
constraining the freedom of the developer in the way the code is
distributed. That’s in contrast to BSD-style licenses, say, where
the developer is free to place additional restrictions on the code,
thus reducing the freedom of the user.