A decade ago the answer would have been obvious. The telephone had only one use: it helped us talk to each other. Now that we can use phones to send text messages – and even pictures – things are more confusing. Of course, innovators and manufacturers inevitably think up uses for their latest invention. Yet it is more than likely that they will have a limited range of ideas compared to those of the users of the technology. Sometimes the phone has been used in ways imagined by innovators and sometimes it hasn’t, but almost invariably the introduction of the phone has sparked unpredicted consequences – even the invention of the phone itself was an unpredicted consequence of work to improve the telegraph. This topic is divided into three parts: the successes, the failures and the consequences of the phone which manufacturers were unable to predict.