Tech Central Station has an article by James DeLong of the Center for the Study Digital Property at the Progress & Freedom Foundation:
The term “open source” means, at its most fundamental, that the code is not secret but public, and thus available for scrutiny. However, the term has acquired some additional meanings. To be regarded as “Open Source” in the computer community, a program must also be available for modification and for unlimited redistribution. The keeper of the flame is the Open Source Initiative, which has criteria and certifies which of the many available software licenses qualify.
Creations other than software could be produced by similar processes. Movement theoretician Yochai Benkler, in a Yale Law Journal article, renames the phenomenon “commons-based peer production,” and identifies a range of applications, from mapping Martian craters to producing ratings on Amazon and eBay. Benkler argues that peer production avoids the transaction costs inherent in both markets and hierarchies, and becomes an alternative “third model of production.”
When it becomes absolutely unavoidable to discuss support, the open source theorists talk about “indirect appropriation,” whereby getting a reputation for solving a software problem might get you hired to solve a similar problem, or where high productivity gets you academic tenure. Or a software programmer writes proprietary works for an employer during the week while doing open source on Sundays. In the background is some economic activity that actually pays the bills while the creator cadges bits of time to engage in his hobby. Or, for the professionalized core, there is some economic entity willing to subsidize the enterprise for its own purposes.
Even for software, the workability of this model is not a slam dunk, and in the software area some very big companies have strong reasons to support the open source movement, as they are indeed doing. IBM, HP, Sun, Dell, and others are putting in billions of dollars, and this is what keeps Linux afloat.
There is nothing wrong with this; it is a sensible business strategy for these companies. But it is not a model that transfers to music, or books, or journalism, or movies, or pharmaceuticals or games, or practically any other form of intellectual endeavor.