AT&T is threatening to punish customers by imposing higher fees on users who consume more data through its wireless service.

Head of AT&T Mobility Ralph de la Vega claims that a small minority of customers is responsible for the majority of data usage:

...just 3% of AT&T smartphone customers use 40% of all smartphone data, and... they consume 13 times the data of the average smartphone customer and make up less than 1% of AT&T's total postpaid customer base.

AT&T's rationale is this: A tiny group of super-users is slowing down the network with all of their downloadin', so they should be charged more for it, since the company's flat rate doesn't cover the costs of providing service.

But AT&T is pulling in such massive profits from its wireless service that there doesn't seem to be much of a financial justification for this scheme beyond the desire to wring even more profit from customers.

To top it off, AT&T is already charging customers $490 per gigabyte of data used once small initial limits are exceeded -- even for customers with "unlimited" data plans. In AT&T's parlance, "unlimited" is actually just 5GB. A few GBs over that limit and you've got a real bill on your hands (a class-action suit is pending). Is AT&T really claiming that $490 per gigabyte is not enough to compensate cover the cost of service?

Even without such insane overcharging, in the last year AT&T has experienced a huge increase in customers who pay the most for data, and a corresponding windfall in profits.

Much of that windfall comes from the iPhone. Out of 4.3 million 3G devices connected to AT&T's network in the third quarter of 2009, 3.2 million were data-rich iPhones. That translates to a 33.6 percent increase in wireless data revenues from last year, or $3.6 billion.

However, some are suggesting that AT&T does actually face serious problems with congestion, because it may have badly misconfigured its network. If that’s anywhere near true, it seems even less appropriate for AT&T to price gouge its customers to compensate for its own mistakes.