To stream all those extra pixels, you're going to need a pretty fast Internet connection: about 15 Mbps. For Hastings, this sounds like no big deal.
"This is very practical," he said. "You can stream 4K over Wi-Fi if you want to."
Technically, you can stream anything so long as you've got a wide enough pipe. And sure, the fact that ultra HD can be compressed into a 15 Mbps stream is impressive in itself.
But 15 Mbps is still a pretty hefty load in a country where the average connection speed still lags at 8.7 Mbps. What Netflix thinks is a reasonable hit to bandwidth would be enough to overwhelm the subscriptions of many Americans. Verizon's DSL offerings, for instance, max out at 15 Mbps. Comcast's Xfinity triple-play package starts out with a 25 Mbps connection. And those are just advertised speeds; your mileage may vary depending on the time of day and the load on the network.
Internet providers do offer faster plans for more money; fiber optic connections, for instance, are becoming increasingly popular. But it's not clear Americans are rushing to adopt those services. According to the Federal Communications Commission's most recent data, more than half of Internet connections in the United States in 2012 were still slower than 6 Mbps.
Chances are the people who plan to watch 4K streams on Netflix will find it easy to pay more for a high-speed broadband connection. But it could take a long time for 4K to become widely adopted by ordinary Americans.
Update: In response to a question, Netflix spokesperson Joris Evers tells me 1080p HD streams at about 5.8 Mbps, about 2.5 times less than what 4K streaming will require. It's also important to note that the 4K stream will not be Netflix's only stream — for devices that don't support 4K resolution, the picture will continue to be streamed in normal HD or standard definition.