You have a million subscribers to your YouTube channel, and every week you upload videos that are instant viral hits. So how do you make a living from your online popularity? As YouTube celebrates its 10th birthday a whole new industry has sprung up around the video platform looking to monetise its emerging talent.Most of the agencies dedicated to "vloggers" (video bloggers) are start-ups, because the scene is still in its infancy.They are performing a vital function: connecting YouTubers to publishers, TV networks and radio stations. They also turn YouTube stars into professionals.Many are teenagers who uploaded videos from their bedrooms and had no idea they would become stars."They're at home and alone and slightly surprised when they put music out there and lots of people like it, " says Conrad Withey, founder of Popshack, which specialises in finding and promoting emerging pop music talent.Withey, former president of Warner Music, founded Popshack after seeing traditional publishers and record companies struggling to deal with the new breed of music artist."I thought there should be a new kind of business discovering that talent."YouTube has become one of the few ways to reach younger consumers. A Variety survey found the five most influential figures among Americans aged 13 to 18 were YouTube stars."Young people don't sit in front of the TV for hours, they sit in front of a laptop for hours," says Dan Is Not On Fire, aka Dan Howell, a 24-year-old YouTuber with an estimated net worth of £2-million. "Media companies have to adapt or die."Withey adds: "The idea that people will send demo tapes to record companies and hope to get discovered is over." ..