Proprietary software and your open source contributions

Having seen the Canonical plans inside and out from various teams within the company (and having Mark as a friend for years) I can tell you that the risk of Canonical proprietary software being created out of the community's open source contributions is pretty much zero. It's just that Mark is a bit of a neat freak. He often worries about complicated, long-term risks and likes the idea of creating process to clean up things which he considers messy. I don't know whether his contributor agreement vision is practical enough to be successful, but he has proven me wrong enough times that I usually give Mark the benefit of the doubt.