Copyright Assignment In Open Source Projects

The issue of copyright assignment for Open Source projects has come up again, this time regarding Canonical. I've been influenced by Michael Meeks' writing on the subject. (If you follow the link to his article, beware there's a theological rickroll!) I'm of the view that the contributor should retain copyright, and not assign it to anyone else. This effectively reduces the asymmetric power that a sole copyright holder has with GPL'd code. A comment on Shuttleworth's article is also against copyright assignment, which brings us nicely back to Canonical.