What could be the secret to £1bn success? YouTube was first sold for $1.6bn (£1bn) of Google shares and Skype for an estimated $2.6bn (£1.65bn). Start-up technology businesses can quickly become huge success stories. But they do all have to start somewhere. Richard Taylor visits the Founders Forum to investigate some of the start-ups looking for the right way to step up from being simply upstarts. Read more: