"Whatever you think of open source software, you have to
acknowledge that Linux has ruined the Windows NT party;
that Apache has spoiled the IIS and Netscape server
games; and that Perl, Python, PHP, and Tcl have made Java far more free and
less lucrative than it otherwise would have been.
How did this happen? Why did these open source technologies spring up at the
very time that their proponents could have made their own billions by playing the
commercial game?" Read the essay at O'Reilly.