A number of Internet service providers, including Comcast Corp. and Verizon Communications Inc., have recently upped the maximum speeds of broadband they offer residential customers to as much as 305 megabits per second.

And Google Inc. is testing a high-speed network in Kansas City that would offer a speed of one gigabit—equal to 1,000 megabits—per second, which the company boasts would allow a person to download a season of "30 Rock" in 30 seconds.

But...