Special K opened up the first ever Tweet Shop in London this week. It's a spot where the brand is promoting a new line of chips (or crisps as they're known across the pond). Visitors pay for a bag of these crisps with a Tweet.

The approach is of course meant to be a way to reach a mass market about the new products. "The value of positive endorsements on social media sites is beyond compare so we’re excited to be the first company to literally use social currency instead of financial currency to launch this new product in our bespoke Special K shop," said Sarah Case from Special K.

The Tweet Shop isn't just a new marketing gimmick. In an era where so many are asking about ROI, this is noteworthy for another reason. By turning a Tweet into currency, Special K is also demonstrating that consumer content has value.

If you're in London this week, the Tweet Shop is open for business through Friday.