Imagine a world where you didn’t need to carry cash, credit cards or your cheque book. It may be just around the corner with cereal company Kellogg’s opening up the world’s first “Tweet” shop in Central London. As Kellogg’s launch their Special K Cracker Crisps, they also dive head first into a new world of marketing. Customers are invited to sample the new crackers before purchase and then post a positive Tweet in exchange for the goods. We guess that positive endorsement is worth a fair bit for Kellogg’s marketing team and if it all backfires we’ll still have some tasty loot.