Michael Dolan has written an interesting commentary on the differences between corporate led open source projects and Foundation led open source projects. He uses Eclipse, Linux, OpenSolaris and OpenDS as examples. It is well worth the read.
In my mind Michael has captured the essence of why it is important to understand the governance model of an open source project. There are two main models emerging for open source projects: 1) Corporate led governance and 2) Foundation led governance. If you look at the type of governance used by the project, you can explain a lot of the behaviour in the project and the community.