Do We Need a Covenant for Open Source Businesses?

It's no secret that businesses built around open source tend to favour one model in particular - that involving dual licensing. The basic idea is simple.

A company acquires the copyright of the main codebase, which might begin life as a small-scale, single-coder project, and is then “taken commercial” thanks to a little greasing of palms (providing a well-earned payback for all those hours of lonely coding.) 

On Open Enterprise blog.