[NorwegianDude]

A lot of people uses stackoverflow for the gamification. Others just want to give something back to the community.

Open source is a great way to market yourself. If I have some really valuable code, then I'll keep it for myself. If I think it would be more useful and gain traction as an open source project then I might publish it and in that way position myself as the top expert on that software.

A lof of businesses are actively using, publishing and contributing to open source. Not because they don't want to make money, but because it's the way to make money.