Last year Kellogg’s opened a pop-up shop in London’s Soho area where people were able to buy their new savoury crisps. The price for the snack? One of your own tweets. People who go into the shop get to try the crisps and if they want to take some away, they spread the word via Twitter about what they are up to. The Special K marketers and agency team tracked tweets through a large LCD screen that follows the #tweetshop hashtag — once a tweet appears, the box of crisps is good to go. The twittersphere is jumping about the notion of using tweets as currency and the snacks are "selling" like hotcakes.