There's a difference between "Linux" and GNU/Linux. The Free Software
Movement (FSF and the community of users and developers) believes software
should be free to run for any purpose, free to be modified and free to be
shared: http://www.gnu.org/philosophy/free-sw.html
This we call GNU/Linux, whereas those who use and develop "Linux" software
are less concerned about the free aspect of software. That's a simplified
version of the differences.
The key to understanding the Free Software Movement is a knowledge of the GNU
Philosophy. Some of the GNU ideas can appear contradictory at times, for
example, GNU says, software should always be free, however free software can
also be sold, for profit.
To learn more I recommend going direct to the source at gnu.org:
http://www.gnu.org/philosophy/philosophy.html
