Why does Comcast Internet service have a 300GB monthly data cap?

When asked that question today, Comcast's vice president of Internet services, Jason Livingood, said that he doesn't know, because setting the monthly data limit is a business decision, not one driven by technical necessity.

"Cable Cares," a parody account on Twitter, asked Livingood, "Serious question, why are Comcast's caps set so low compared to the speeds they're being sold at? 100mbps can hit 300GB in 6hr~."

"No idea—I'm involved on the engineering side to manage the measurement systems but don't weigh in on the business policies," Livingood responded.

We've asked Comcast officials if there are any technology benefits from imposing the caps or technology reasons for the specific limits chosen but haven't heard back yet.

Livingood's statement probably won't come as any surprise to critics of data caps who argue that the limits raise prices and prevent people from making full use of the Internet without actually preventing congestion.

Comcast, the nation's largest cable and broadband provider, has claimed that its data caps are not actually "data caps," because customers can use as much data as they want. They just get charged extra when they exceed the monthly limit. This is the same setup used by wireless carriers; pretty much everyone calls them data caps, and that's what we call them, too.

For now, Comcast only imposes the caps in parts of its territory and doesn't charge the overage penalty until the fourth time in each 12-month period that customers exceed the cap. This is to help customers "get accustomed to the new data usage plan," Comcast says. The overage penalties are $10 for each additional 50GB.

A year ago, Comcast Executive VP David Cohen said the data caps could be rolled out across Comcast's entire territory within five years.

The caps aren't applied identically to every service plan. Some higher-speed services have caps of up to 600GB, while Comcast's new 2Gbps fiber-to-the-home service reportedly doesn't have a cap. On the other hand, Comcast offers a "flexible-data option" with extremely low limits. Instead of 300GB per month, the flexible-data option provides just 5GB of data each month and charges customers an extra $1 for each gigabyte they use beyond the 5GB. Customers on this plan get a $5 credit if they do not exceed the 5GB limit.

Comcast set a data cap of 250GB per month in 2008, saying that its policy was to "contact the top users of our high-speed Internet service and ask them to curb their usage." Comcast suspended the 250GB cap in 2012, replacing it with the current system with overage fees.

The data caps of Comcast and other providers may soon come under additional scrutiny at the Federal Communications Commission, which is required by Congress to take action if broadband isn't being deployed to all Americans in a reasonable and timely fashion. In the past, the FCC's annual broadband deployment analyses have focused on speeds and availability. But the commission's next analysis may evaluate whether pricing and data caps are also preventing adoption of broadband.

Late last year, the US Government Accountability Office urged the FCC to examine data caps closely, saying that providers who face little competition may abuse caps to impose higher prices on consumers.

When the GAO surveyed Internet providers, wireline companies told government officials that "congestion is not currently a problem," but that usage-based pricing would generate more revenue to help fund network capacity upgrades.