Mark Tutssel, worldwide chief creative officer at Leo Burnett, said successful future campaigns would need to imitate viral content - easy to repeatedly consume and pass around, writes the Financial Times. Speaking at the Cannes Lions International Advertising Festival, he said marketers need to learn from consumer-created content, citing websites such as YouTube.com.

"Marketers must learn to let go of the control they think they have over their brand…. Once consumers have interacted with brands, they will not go back to being shouted at by marketers," he is quoted as saying.

The speech came as the Lions awarded a Grand Prix to a campaign designed to look like a homemade internet video, ostensibly showing graffiti artist Mark Ecko defacing Air Force One.