The world's biggest gallery: How street art became big business

Street art was once seen just by passing pedestrians. Now, the internet has revolutionised the form, and it's not only Banksy who is transforming our cities

Street art used to be very much a minority taste. Enthusiasts would venture out, at the dead of night, armed with spray cans. They'd use them to jollify a wall, or bridge, or subway train. Sometimes, their work might be very good indeed, but its audience would be limited to whoever happened to wander past. An artist's only brush with notoriety came when newspapers reported their latest court case.

Then the internet came along and changed all that. In a little over a decade, a genre that was once dismissed as vandalism has used cyberspace to gain credibility as one of the most vibrant and creative scenes in urban culture. Inspired by Banksy, who has completed the journey from viral sensation to millionaire creator of $60,000 canvasses, Oscar-nominated movies, and bestselling books, a generation of artists is now starting to fashion lucrative careers out of their former hobby.

"Today, somebody does a tag in Russia, China, Japan, or Africa, a friend photographs it and within a few hours it'll be viewed on websites all over the world," says Jeffrey Deitch, director of the Museum of Contemporary Art in Los Angeles, which recently opened a major show on the subject. "I think you can make a good case that street art is now the most influential art movement of the past 30 years. The penetration of urban culture is huge, and it's influencing everything from skateboard design to high fashion. Some of these guys have even been hired to design Louis Vuitton handbags."

Central to this rise has been Sebastian Buck. An English enthusiast, based in LA, he founded the website Unurth in 2008. It has since become one of the most influential street art forums, helping discover and champion such rising stars as Roa and Escif, as well as established "names" like Blu, JR and OS Gemeos. On the coming pages, Buck profiles some of the most exciting talents working on what is now the art world's largest canvas.