The fashion industry and the social media

A select audience of 1,500 people was invited to watch a live stream of the Burberry show during London Fashion Week. They could chat with other using Twitter and Facebook and order the clothes before the show had even finished. Burberry promised to deliver anything ordered to a costumer's home within seven weeks — a far cry from the usual six-month turnaround for its spring and autumn collections.

That "shop the runway" technology is powered by Createthe Group, founded by James Gardner, who had helped pioneer algorithmic trading when he worked on Wall Street. "It's a very powerful way to build long-term relationships with customers," Gardner told the BBC. "They're seeing new clothes at the same time as the buyers."

Burberry is not the only fashion business using social media. Louis Vuitton works with the location-based service FourSquare — which lets your friends know exactly where you are — to make people who visit its stores show up as "Vuitton insiders", while Ralph Lauren has iPhone apps for its preppy Rugby brand. These let users create their own styles and then share them through Facebook.