Navigating the Open Source Ocean

A paradigm is a mental model of something - a helpful way of grasping its essentials. Although the term "new paradigm" is much overused, the open source approach to software development definitely merits this description - old mental models simply do not apply to this emerging industry.  If familiar paradigms don't apply to open source software, what's a good way to start to grasp its nature? One approach is to explore a metaphor based on images of islands in a gray ocean that, if it does not fully capture the essentials of open source software, at least illuminates some important aspects of it.