Dallas, we have a problem!  Bandwidth hungry customers armed with iPhones and the availability of over 200,000 apps, are straining the AT&T wireless network. The new iPhone 4 with video calling (FaceTime) and HD video recording, will only further tax the network.  Economics provides a fairly simple answer when the demand for bandwidth exceeds the supply - raise your prices.  Which of course is exactly what AT&T has done.
 

AT&T faced with imposing even more demands on their already strained network, created a pricing plan that will force the high bandwidth users to either pay for their share of network usage or look for an alternative elsewhere. AT&T chose to create a tiered pricing plan that lowered prices for most customers, but also makes users pay for bandwidth usage. They had to know that they risked creating a negative response from the market place.  In fact, you can bet the lower priced plans were offered to minimize the negative aspects of a tiered pricing plan.