In 1991, a computer science student named Linus Torvalds made public his Linux kernel. With much effort, the GNU system and the Linux kernel were combined to create what is now commonly referred to as Linux. Some distributions include non-free software and demonstration versions of commercial applications, much to the displeasure of dedicated free software adherents. He discusses each of these in some detail, and I have nothing to add beyond the observation that all of these challenges are just specific examples of a more general problem. This shift in demographics, and the resulting interactions between the various groups, is the root cause of all the problems faced by the Free Software Movement.
Zeal describes the extent to which a hacker believes in and supports free software.
The other is a measure of the hacker's hostility toward the idea of commercial software and the companies perceived to dominate the commercial software market. Had this not been the case, the GNU Project would likely have died very quickly. But the membership of the FSF and the GNU Project make up an increasingly smaller part of the Free Software Movement. Whereas the FSF continues to be very zealous and seriously anticommercial, the Open Source movement, although still dedicated to providing free software, has attempted to distance itself from the FSF's more confrontational, anticommercial stance. The free software community seems to have more than its share of very vocal and entirely clueless individuals who spout catchy slogans, flame message boards, pirate software, and generally make nuisances of themselves.