Through it all, Roku has sold as many devices in the past 18 months as it did in the previous five years, announcing in September that it's topped 10 million total units. According to a July report from Parks Associates, 44 percent of U.S. homes with a streaming device use Roku, topping Apple's 26 percent.

Google has been trying to crack the connected TV business for years, most recently with its $35 Chromecast stick in 2013. And, of course, there's the $99 Apple TV.

On Monday, Amazon introduced the Fire TV Stick , a $39 dongle that plugs into a Web-enabled television's HDMI port. Roku, which has been on the market with streaming boxes since 2008, introduced its owns stick in late 2012 and sells it for $50.

Roku CEO Anthony Wood has grown so accustomed to fending off the world's largest tech companies that Amazon.com's deeper dive into the streaming TV market is little more than a calendar item.

"Our sales have never been better," Wood said in an interview. "Every time these things happen, the market grows and sales accelerate."



Amazon jumped into the hardware side of the market earlier this year with a $99 streaming box, joining a crowded field that includes Apple, Google and TiVo. They all allow customers of Netflix, Hulu and HBO Go to watch shows and movies on demand along with an assortment of sports, news and music channels.

With HBO and CBS rolling out streaming-only options, there's a land grab for consumers seeking alternatives to traditional pay TV.

Wood says that Roku has several advantages over its deep-pocketed rivals. In addition to being first to market and having over a half decade of experience, Roku's singular mission is to sell boxes and promote the services on top.

Amazon, Apple and Google, meanwhile, compete elsewhere, and are inclined to promote their own products over others. Neither Chromecast nor Apple TV, for instance, includes Amazon's Instant Video service.

"We have more content, it's simpler to use, and we're neutral," Wood said. "Everyone else has an agenda."

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And because streaming is the heart of Roku's business, it has the attention of the entire 300-person company.

But Roku is no longer just about selling end-to-end devices with its own hardware. The company is licensing its software to serve as the operating system for Web TVs. Asian manufacturers Hisense and TCL are selling Roku-powered TVs that have all the capabilities of streaming along with connecting to whatever cable box, game console or Blu-ray player a consumer uses. It's similar to a model that Google and Yahoo have unsuccessfully tested.

Growing faster than its hardware or licensing business, Wood said, is the company's advertising unit. Roku is showing display ads on its main menu, promoting films like "Dawn of the Planet of the Apes" or "The Lego Movie." Some channels offer free ad-supported content, where the commercials come from Roku's stable of advertising partners.

That all adds up to a higher margin business than one that relies solely on selling boxes and sticks. Better profitability has made it easier to attract investors, which was historically a challenge for Roku.