A Comcast executive said he expects the company will roll out "usage-based billing"—what most people call "data caps"—to all of its customers within five years.

Speaking with investors today (transcript), Comcast Executive VP David Cohen said, "I would predict that in five years Comcast at least would have a usage-based billing model rolled out across its footprint."

Comcast, which has about 20 million broadband customers, has rolled out caps to some of the areas that it serves, including Huntsville and Mobile, Alabama; Atlanta, Augusta, and Savannah, Georgia; Central Kentucky; Maine; Jackson, Mississippi; Knoxville and Memphis, Tenessee; and Charleston, South Carolina. Customers generally get 300GB of data per month, with $10 charges for each extra 50GB. (During the trial period, customers can exceed the cap for three months out of any 12-month period without incurring extra fees.)

Comcast told Ars last November that "98 percent of our customers nationally don’t use 300GB/month." Cohen today said that Comcast will raise the limit over time so that the large majority of users won't go over it, suggesting that 500GB is a possible monthly limit five years from now.

"I would also predict that the vast majority of our customers would never be caught in the buying the additional buckets of usage, that we will always want to say the basic level of usage at a sufficiently high level that the vast majority of our customers are not implicated by the usage-based billing plan," Cohen said. "And that number may be 350—that may be 350 gig a month today, it might be 500 gig a month in five years."

When asked if customers will get a "reasonably large number of usage plans" to choose from, Cohen said he doesn't want a situation where "80 percent of our customers are implicated by usage-based billing and are all buying different packets of usage. I don't think that's the model that we are heading toward, but five years ago I don't know that I would have heard of something called an iPad. So very difficult to make predictions."

Comcast has offered a few different data package options during its trial period. Some trials varied the caps from 300GB to 600GB depending on which speed tier customers paid for. "We don't want to chase our customers away, so we are rolling out different models, different approaches," Cohen said. "We are surveying our customers.

Comcast is attempting to purchase Time Warner Cable, which has rolled out 30GB plans in exchange for $5 off the monthly bill. Those plans are optional, though, and most TWC customers have stuck with their unlimited data packages.

The government could conceivably require Comcast to maintain unlimited plans in Time Warner Cable territory, but Cohen doesn't think it will. "I doubt it [will be a factor] in the merger review because it really has nothing to do with our transaction. It's a generic industry-related issue," he said.

However, Cohen said he "wouldn't be stunned" if the FCC considers data caps in its deliberations on net neutrality rules "because people have tried to make this an open Internet issue."