I had quite an epic trip this morning trying to buy a pay-as-you-go iPhone without handing over a whole load of personal data. Carphone Warehouse’s purchasing system demanded my details. The Apple Store’s hordes of condescending staff seemed to have little else to do except tell me it was “impossible” to buy the miraculous device without handing over personal information. Finally, somebody at an O2 store sold me the bloody thing anonymously.

Here’s a simple value-devalue analysis. Benefit to Carphone Warehouse/Apple of my name and address — pennies. Cost of demanding this personal information — £400.