James,

I'd agree with you on something like the forums, but that's a very generic item. What about SugarCRM? I could easily add customizations, like phone/VOIP integration, automation to some customer process, links to something like Dynamics, etc. that would give me a competitive advantage. It would be up to me to decide to what extent that I'm helping competitors with that.

what about GIMP? Or some editing/rendering process. It might be that I gain some advantage I don't want to share.

I don't necessarily disagree that releasing back code is a bad idea. And lots of companies do release back stuff. But many are afraid and they're not sure they want to.

I can buy commerical software, like SAP, and customize it as well. That's more along the lines of what I was originally writing about. The forums might not have been a great example. They're somewhat open source. You can buy a license to get the code, but you can't freely release it.