Iain really liked this campaign and bracketed it with Burger King's Whopper Sacrifice. While I like it, it's not much more than a digital version of the traditional promotional competition. The key for me is that it's utilising technology rather than the behaviours related to that technology. It works but it's not new.
Social media and digital aren't inherently new behaviours, they're new technologies/ecosystems that facilitate existing behaviours. But where Burger King was really smart was in placing a new version of that behaviour - Facebook friending - at the centre of its interaction. A behaviour that hadn't existed without the technology.
Marketing is all about behaviour, but changing behaviour is really difficult to do. It's much smarter to adapt your marketing to existing behaviours in a way that gets the user to think about your product/service and perhaps become inclined to change another behaviour.