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MOUNTAIN VIEW, Calif. -- The Chromecast was never part of Google's [X] division, but that doesn't mean that the company will let you see the living room test lab set up here for Chromecast evaluations. At least, it's not likely without a hefty nondisclosure agreement.

As described by Chromecast's vice president of product management, Mario Queiroz, the faux living room has all the trappings you'd expect. There are couches, televisions, and, in typical user experience lab fashion, a one-way window through which Google experts can evaluate how participants are getting along with Google's popular and low-cost streaming media dongle (read CNET's Chromecast review).

Google has big plans for Chromecast in 2014, having finally scored an unequivocal hit at connecting media apps to your TV after years of near-misses and not-even-close-misses. Google has revealed plans for international Chromecast distribution and widespread app support later this year. According to Queiroz, the $35 Chromecast represents Google's desire to integrate your various media obsessions into one streamlined device.

"Our goal has always been to make it so that there wouldn't be a separate implementation for mobile and TV and set-top boxes," he said.

Never mind the nascent media services on Google Play and other Google initiatives, though. There's this one particular service that Google has been obsessed with for years: YouTube.

"YouTube was an important driver. Google wants to get YouTube onto as many screens as possible," Queiroz said.

"They're obviously building on the popularity of YouTube and streaming online videos, but the simplicity of it makes it appealing to a lot of different demographics in their market," said Greg Reinecker, a senior industrial designer at Axis Design, a consulting firm in Austin, Texas. "I think there's a lot of similar products out there that are harder to use."

But when it comes to hardware that lets you watch YouTube and other services on your living room TV, Google has struggled. Google TV is currently undergoing a refresh, and the streaming media ball known as the Nexus Q was kneecapped before it could properly fail on the open market. Then there's the fact that those devices ran one flavor or another of Android. By contrast, Chromecast, as its name indicates, runs on a stripped-down version of the Chrome operating system that powers Chromebooks.

Why Chromecast worked

It wouldn't be the first time that Google has bet on more than one horse in a race, but Chromecast's overnight success marked the first time that Google was able to cross a given finish line with a popular hit. It took Google a month-and-a-half to two months to ramp up production to meet demand after the product launched, Queiroz said. That kind of popularity relies on more than just a low price.

Queiroz said that Google experimented a lot with the dongle and kept refining it after launch. The team changed the manufacturing to make it clear that the USB end of the adapter goes into the power adapter, and added a narrow HDMI extender to accommodate televisions that didn't have enough space around the HDMI port.

Each decision about what to change became "harder to make," he said, because of the goal of keeping the entire device simple.

Axis Design's Reinecker said that while Google remains a "software first" company, it put a lot of time into developing the dongle.

"It's as small as possible. I've seen pictures of the circuit board and antenna and it's very tight," Reinecker said. "They were thinking that it's got to disappear."

In fact, that was precisely Google's intention, Queiroz said. Not only did Chromecast have to be simple physically, but it had to be simple to use, too.

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"The easiest user interaction model is simply no user interaction. We've gotten it down to a button," Queiroz said. That's a bit of an understatement on how to set up the Chromecast, but not by much.

"You just open the front flap, there's some diagrams that explain where to plug it in, and you're good to go. There's not a bunch of fussing with the box, instruction pamphlets, pages, anything like that," said Reinecker, adding that it's a tip of the hat to the design masters at Apple. "The packaging supports the product."

Brian Blau, a consumer technology analyst with Gartner, agrees that the simplicity of its design interaction has helped propel adoption. Even though the Chromecast has competitors, "it just works, and that is sometimes a difficult feature to get right," he said.

No easy path forward

Now that people have accepted the device as a low-cost way to get the Internet on their TVs, Google will face new challenges to lock in Chromecast's success.

Queiroz and his team plan to stabilize the tab casting feature, which lets users send a Chrome browser tab to Chromecast. It's complicated because they've yet to figure out how to effectively buffer changes to the Web page and "cast" them to the TV.

Another big challenge is ensuring that Google properly anticipates the services offered on Chromecast as it goes international later this year. In some markets, people just want YouTube, while England, Germany, or Japan might have a more diverse selection of favorites.

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How people can figure out which apps work with the dongle is yet another one that Google has begun to address on the Chromecast apps site. Queiroz also said that apps that can use the Chromecast to get your personal content, including videos, music, and photos onto your TV are often requested.

The planned Google Cast SDK will help app developers along, while Google is working with manufacturers to build more Chromecast hardware.

"It will be analogous to how we do Chromebooks and Nexus devices," Queiroz said. Hitting that sweet spot of simple design, low price, and enough apps to drive adoption won't be easy, which is why Queiroz said he's less concerned about additional Cast hardware than he is about moving into other countries.

He says that he can tell the Chromecast design is winning over people so far because of two factors: what he described as a "very good holiday season" in terms of sales, and how the Chromecast telephone support line is getting used.

"The good thing is that the phone lines were quiet," Queiroz said. "Our call centers were bored."

That may be, but it'll be the challenge of expanding in the coming year that will determine whether the Chromecast has staying power.