What are the benefits of open source software model to original software writers?

I am interested in what the benefits of open software model are to original software writers (not users). I more or less understand the concept from users standpoint (they can modify it, just like Linux, etc.) What I would like to know is what would a developer gain by releasing his software into community. He cannot charge for it anymore, even if he still holds IP rights like patents. Charging for support, not licenses? Quick market penetration? What else? Thanks.What are the benefits of open source software model to original software writers?
Customers. He charges for maintenance, usually. Also Open Source programs are often tickets to big money jobs at companies like Google or, in the case of the Mach kernel writer (Mach kernel being the one that runs Mac OS X GNU Hurd and GNU Darwin) a job at Microsoft. Miguel de Icaza was actually hired by Microsoft, but US Immigration said "You can't have him because he never went to college" so he co-wrote the GNOME desktop and now he works for Novell.





Open Source Software is a calling card. Red Hat is doing very well as an Open Source company so don't knock it.What are the benefits of open source software model to original software writers?
You can give your software for free to individuals, but can charge money to professional users. Many open source software writer writes programs for fun, as they are already working in some IT company. So they are not interested in money. Like google you can get traffic, by availing the free software from your website. More traffic means more advertising. I stole this idea from google. Or else you can publish trial version for free, but can charge money for pro version.



In the end I also don't know what are the true benefits, so plz ask others and thnx for 2 points. :)