I recently did a write up trying to explain the concepts and incentives for writing and using Free & Open Source Software (FOSS). It's in Norwegian as the original thought was to shed light on what FOSS is for government officials and other decision makers that represent and affect me, so that they can have an easily digestible resource for understanding what it is. Feel free to comment and if you like the document or disagree or want to make an addition or amendment please follow the contribution instructions.
The document is available at www.simernes.com/open-source