I have always been a crisp snacker and seeing the modern advert boards I was determined to find one for myself. So whilst walking down Oxford Street I spotted an advert at a bus stop for the Do Us A Flavour, Cheesy Beans on Toast. The board asks you to 'Tweet to Eat' and then acts as a virtual vending machine.
It was really interesting and a completely new method in advertising. The crisps itself might be free but the advertising that Walkers are gaining from Twitter and other social medias probably compensate this.
Why not try and find one of the boards around London and have a go! Or just have a read here, campaign-of-the-week-tweet-to-eat.