The boss of micro-blogging site Twitter has identified the tech giant Apple as his firm’s “mentor” and Facebook its enemy, despite launching a new layout some have likened to Mark Zuckerberg’s site’s latest design. Dick Costolo said Twitter and Facebook were competing for the same advertising revenue. But the Twitter chief executive said that, when it comes to Apple, he sees a friend. He said: “Apple is in many ways a mentor company for us”, adding that the two firms had “a great relationship”. However, referring to Facebook, he said: “we’re very different companies”, adding that they were pitched against each other in the same market.