Intuitively, I think open source development should be much more "casual" than industrial development process (like in Microsoft). Because for OSS development:

• Duty separation is not that strict than in big companies (maybe developers == testers in open source development?)
• People come in and out of the open source community, much more frequently than in big companies

However, above are just my guesses. I really want to know more about the major difference between the open source and industrial development. Is their division of duty totally different (e.g., is there a leader/manager-like role in open source development?)? Maybe it is their communication style that differs a lot? Or their workflow?

Please share your opinions. Thanks a lot!