Who are the people responsible for the development of open source software?
I agree and disagree with Ullyses on this. Open source is developed by anyone, that is the point of OSS, the source code is distributed so that it can be enhanced and improved upon. How ever I tend to disagree that OSS is not developed as much as closed source software. The current trend is moving towards OSS and the amount of OSS projects is huge and moving more towards the mainstream. It is also not just about stopping Microsoft, it’s about software development. You cannot effectively develop usable software with a closed source.
The point of it being open source is that somebody creates a piece of software and places it on the net where anyone can use it and develop it. All the coding is open to development. So your answer is anyone who uses the internet might develop open surce software. Of course the reality is that only those who are interested in learning a bit about real computing and stopping microsoft from getting even richer are the ones who develop open source, so it is less developed than the stuff that microsoft chuck to use us as guinea pigs for.