In the early days of mobile Internet, bandwidth was not an issue, so price plans were quite simple, very often expressed in the form of a flat rate or "All you can eat" pricing. As long as capacity was greatly available, this was a convenient and simple way to define a tariff, both for the end-user and the service provider. With the tremendous growth of data traffic observed recently, bandwidth becomes more and more a scarce resource. Consequently, flat rate pricing leads to a minority of heavy users cannibalizing the whole resource, while being subsidized by low users. This is of course not acceptable! It is neither fair for the majority of end-users, nor profitable for the service provider.