So we may be focused on all things digital but this is a pretty effective and tactile way in which Coca-Cola have embraced (or not embraced) what would normally be a digital billboard.
The audience now may well expect billboards in shopping centres like this to be digital. This is beautifully simple, getting passers by to engage with the poster and in turn the brand. Then taking that brand home and giving it to someone else.
It’s a marketing dream.