Investors like Craig Moffett have been urging AT&T to ditch the $30 unlimited pricing model and start charging customers more money for wireless data in the form of steep overages. While there's some customers who think a more usage-based approach is a good idea, they usually fail to understand that when carriers implement such models, they frequently don't offer improved value, and users wind up paying higher prices. If you're one of the many iPhone users who like the $30 unlimited data model just as it is, things may be changing soon according to AT&T's wireless division boss:Of course for every user who's gobbling up a lot of data, there's dozens more paying $30 a month simply to access their e-mail occasionally. In the end, AT&T's consistently made more than enough money to keep pace with user demand without changing iPhone data pricing models -- they just failed to meet capacity demand. The result has been a very bad public relations year for AT&T, as consumers reacted to an AT&T wireless network that wasn't ready for the iPhone. That's AT&T's fault -- not the fault of flat-rate $30 pricing, or the fault of customers who simply want access to what was advertised.

While AT&T (and every other carrier) likes to pretend that the shift to the overage model is driven by things like "fairness" or necessity, the reality is the push is driven by investors for one reason: it winds up with you paying AT&T more money for the same (or less) service.