Really for the alpha and beta geeks among you, Tim O'Reilly has a great, lengthy essay on the current state of open source. It provides a decent history of the movement, and a prescription for its success in the future.
I have a simple test that I use in my talks to see if my audience of computer industry professionals is thinking with the old paradigm or the new. "How many of you use Linux?" I ask. Depending on the venue, 20-80% of the audience might raise its hands. "How many of you use Google?" Every hand in the room goes up. And the light begins to dawn. Every one of them uses Google's massive complex of 100,000 Linux servers, but they were blinded to the answer by a mindset in which "the software you use" is defined as the software running on the computer in front of you. Most of the "killer apps" of the Internet, applications used by hundreds of millions of people, run on Linux or FreeBSD. But the operating system, as formerly defined, is to these applications only a component of a larger system. Their true platform is the Internet.
Some of the themes of this essay are reflected in O'Reilly's state of the union address at the O'Reilly Emerging Technology conference.