For people in the Windows world, Bruce Byfields' A Field Guide to Free Software Supporters will help them understand the various groups that make up the free software/open source software movement:
When you look, there are at least seven different types of FOSS supporters.
To outsiders, these schools of thought are more similar than different. In the same way that many Europeans see few real differences between a New Englander and a Californian, outsiders may see little to distinguish a Softcore Advocate from an Activist.
It is a great piece.
This is a great starting point for anyone that is getting involved in FOSS. Understanding that these groups exist and their positions will make it much easier to understand the dynamics of development and advocacy that you will run into while working with the FOSS community.
I feel that this article could be expanded on in a few areas, but eventually this could become a great taxonomy of the FOSS movement.
For instance, I think that there is room to dissect the editorialist advocate. This is the do-as-I-say-not-as-I-do advocate which will praise and preach open source, freedom, open systems, open standards but yet always ends up using the latest-and-greatest proprietary, DRM-enabled, crypto-locked gadgets and software.