AT&T on Sunday confirmed that it will impose a 150GB data cap for its DSL customers, effective May 2.

AT&T on Sunday confirmed that it will impose a 150GB data cap for its DSL customers, effective May 2.

Users who exceed 150GB will be charged $10 for ever additional 50GB they consume. The company said that less than 2 percent of its customers will be affected; the average DSL customer user about 18GB per month.

"We are committed to providing a great experience for all of our Internet customers. Less than 2 percent of our Internet customers could be impacted by this approach - those who are using a disproportionate amount of bandwidth," AT&T said in a statement. "We will communicate early and often with these customers so they are well aware of their options before they incur any additional usage charges."

AT&T said it will notify customers when they have exceeded 60 percent, 90 percent, and 100 percent of their monthly data allowance. The provider will also provide access to a usage report as well as tools like a usage calculator and examples of the kind of activity that will eat up data.

The data caps were first reported by DSL Reports, which said that U-Verse high-speed Internet customers will have a 250GB cap, which AT&T also confirmed.

Reports of a 150GB data cap for AT&T customers dates back to 2008. At that point, for new customers in Reno, Nevada, allowing them to use between 20GB and 150GB of bandwidth per month depending on their speed tier.

That came one month after Comcast announced that all its residential customers would be . Comcast had come under fire in 2007 for to customers who consumed a large amount of bandwidth but refusing to provide those customers with information on how much bandwidth they were able to use. That led to accusations of Comcast cutting off access to P2P services like BitTorrent, an FCC enforcement action, and a net neutrality debate that continues today.

That year, Time Warner Cable also experimented with bandwidth caps, but a public backlash prompted the provider to in April 2009. Time Warner took some heat because its caps were relatively low  between 5GB and 40GB. The company eventually announced it would also offer a and for $150 per month, but by then, and interest groups were circulating online petitions against the caps.

Editor's Note: This story was updated at 10:45pm with info about U-Verse.