The much-loved Cadbury’s Gorilla ad netted the film category Grand Prix at Cannes, but shares it with the Xbox 360 Halo 3 viral campaign from McCann Erickson San Francisco. I think the Halo 3 ad is quiet, understated and impactful in the way that very few ads are without becoming a discussion topic at every public gathering that includes industry professionals – and even some that don’t. The Gorilla ad, for example, has been spoken about by anyone who’s ever seen it. By contrast, the Halo 3 ad sort of slid through the grills and broke the gate open in a very unobtrusive manner. I haven’t heard anyone mention it.