The Open Source Paradigm Shift by Tim O'Reilly

While a little bit old now, this article by Tim O'Reilly, which is an adaptation of a speech he has given in the past, makes some excellent points and is a good read. My two favorite clips:
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.
and
In short, if it is sufficiently robust an innovation to qualify as a new paradigm, the open source story is far from over, and its lessons far from completely understood. Rather than thinking of open source only as a set of software licenses and associated software development practices, we do better to think of it as a field of scientific and economic inquiry, one with many historical precedents, and part of a broader social and economic story. We must understand the impact of such factors as standards and their effect on commoditization, system architecture and network effects, and the development practices associated with software as a service. We must study these factors when they appear in proprietary software as well as when they appear in traditional open source projects. We must understand the ways in which the means by which software is deployed changes the way in which it is created and used. We must also see how the same principles that led to early source code sharing may impact other fields of collaborative activity. Only when we stop measuring open source by what activities are excluded from the definition, and begin to study its fellow travelers on the road to the future, will we understand its true impact and be fully prepared to embrace the new paradigm.
–jeremy