Comcast says it could begin capping monthly data for all its customers within the next five years, a change that could potentially end up costing some heavy internet users additional fees. Speaking at a media summit in New York earlier today, Comcast executive David Cohen said that he expects the company to move entirely to a "usage-based billing model" in the next five years, while adding that most customers don't go over their monthly allotment.

"Very difficult to make predictions."

"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 told the audience. "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 currently has what Cohen described as a "series of pilots" in various parts of the country that determine how much data monthly internet subscribers get. Users in some markets get a 300GB monthly cap, while others get 600GB. In places like Alabama, Atlanta, and Tennessee, there's also what Comcast calls a "flexible-data" option that is limited to 5GB, but offers a credit if users stay under that amount. Those who go over pay by the excess, just like running over minutes on a monthly cell phone plan.

The news comes as Comcast is in the throes of merging with Time Warner Cable, a deal worth $45 billion, and could close later this year. Time Warner was originally sought after by Cable provider Charter as far back as November of last year, but Comcast ended up making the deal happen some three months later. Time Warner already has 30GB plans that run in a similar fashion to Comcast's flexible-data offering, complete with a monthly credit to those who stay under the total.

The last time Comcast made a big change to its data plans was two years ago, getting rid of its controversial 250GB monthly data cap, in place of the 300GB plans. Those who go over the monthly allotment were originally threatened to have their service suspended for a year, though Comcast has since started charging for extra chunks of data.