Big sums are at stake. Mobile operators have invested £40bn ($69bn, ??58bn) in the UK alone on third-generation licences and infrastructure: they are hoping that television and music offerings will motivate consumers to trade up to 3G. Content owners, in turn, know that audiences are spending more time away from home, away from the television. The growth of personal video recorders, iPods and video on demand, coupled with the success of text-message voting for reality television programmes, has also shown them that personalisation and interactivity are trends they could cash in on.The important questions, however – how big this market will become, which of the rival technologies will win out and how the value will be split – will not be fully answered until the players have invested significant sums in mobile television. Moreover, some early studies of the potential size of the market provide grounds for caution.