It ended with a raging Ralf Little, the Royle Family actor, setting about garden gnomes with a golf club on London’s South Bank. But it began as an experimental form of advertising for Microsoft’s Windows Live mapping service on KateModern, an online teen drama series that is helping to remake the business model for web video.

In clips posted on the social networking site Bebo recently, the audience watched the adventures of a group of friends in London and contributed ideas as the drama unfolded. At one point they saw Little’s character Gavin abusing an intern in his computer business, only to find the victim turn­ tormentor by stealing a hard drive and hiding clues as to its whereabouts in garden gnomes around London.