used to sell virtual goods, such as Adidas trainers, or virtual versions of actual cars, or simply to create brand awareness in the real world. Some, such as IBM, are using them as serious business tools by holding international management conferences, thereby eliminating the need to worsen global warming by flying executives all over the world to a place they can meet. Optimists within SL even nurture hopes that the Linden dollar (the in-house currency that is convertible into real dollars) could eventually become a micropayments system for the internet as a whole. There are regular rumours that some of the giant corporations may launch virtual worlds themselves, either as 3D intranets, or to produce a more stable experience than SL has so far managed to achieve. Virtual worlds reached some kind of milestone last week when they held their first annual conference - although, curiously, it was located in New York, not in a 3D simulation. They need time before they gain the courage of their own convictions. Speaking at the Guardian Mobile Business Summit 2012, Horace Dediu of Asymco discussed some of the key questions which will decide the future of the mobile industry, showing where mobile technologies are today and how different mobile manufacturers have risen and fallen over the past half decade.