While Roku (ROKU 1.29%) isn't expected to release its full Q4 2018 results until early February, the company provided investors with a sneak peek at selected metrics from the just-completed quarter, and by all accounts, it appears to have been a blowout. While it doesn't provide a full picture, it does indicate that the growth Roku has achieved through the first three quarters of the year appears to have continued into the company's important holiday period.

The preliminary data showed that Roku's decision to focus on expanding its platform continues to bear fruit, as viewers are not only flocking to its programming, but they are consuming more content when they do. Let's take a look at the data that Roku provided, and what it means to investors.

A TV featuring Roku's user interface and shows to watch.

Both viewers and streaming hours are soaring. Image source: Roku.

More viewers

Roku said that more and more consumers are shifting to streaming and away from linear TV. In a press release, the company estimated that active accounts topped 27 million, an increase of 40% year over year. This marks the sixth consecutive quarter -- every quarter since the company went public -- that it has grown its active accounts by 40% or more compared to the prior-year period.

Operating Metric

Q4 2018

Q3 2018

Q2 2018

Q1 2018

Active accounts

27 million (estimated)

23.8 million

22 million

20.8 million

Year-over-year change

40%

43%

46%

47%

Data source: Roku.

The revenue that Roku earns from its platform business is primarily advertising, so the more people that are watching, the greater its reach, and the more lucrative its ad market will be. That strategy is working. During the third quarter, overall sales grew by 39% year over year, but was led by platform revenue, which topped $100 million, an increase of 74% compared to the prior-year quarter. By comparison, player revenue of $73 million grew just 9% year over year.

More streaming

The increase in customer accounts is also increasing the number of hours viewers are streaming programming on Roku's platform.

Operating Metric

Q4 2018

Q3 2018

Q2 2018

Q1 2018

Streaming hours

7.3 billion (estimated)

6.2 billion

5.5 billion

5.1 billion

Year-over-year change

68%

63%

57%

56%

Data source: Roku.

Not only are more customers watching, but each viewer is watching more. The number of hours streamed by each active account is increasing, hitting 270 hours per account, an increase of 21% compared to the prior-year quarter. However, the most important takeaway from this table is that the year-over-year growth of streaming hours is accelerating overall.

"Strong active account growth and accelerating streaming hours point to consumers' growing enthusiasm for streaming, making Roku America's largest and fastest growing TV streaming distribution platform," Roku CEO Anthony Wood said in a prepared statement. "In 2018, we maintained our leadership in streaming players, licensed smart TVs and TV streaming hours. Roku continues to bring viewers more choice, great value, a compelling user experience -- and lots of TV fun."

That ain't all

Roku gave investors other reasons to be enthusiastic about the future. The company recently announced that it would be adding premium subscriptions that viewers can access and subscribe to via The Roku Channel, including Showtime, Epix, and Starz, as well as a number of lesser-known channels.

The company also announced that new TV models were on the way. Roku said it would partner with Westinghouse Electronics, the latest manufacturer to join its licensing program, to produce HD Westinghouse Roku TV models, which will debut during the first half of 2019. The company will expand its existing partnership with TCL to collaborate on 8K TCL Roku TVs that will hit the market in late 2019. Additionally, some TCL models will feature an integrated high-performance far-field mic array, which will allow viewers to control the TV with their voice. 

Investors appeared to embrace the preliminary earnings news, bidding up Roku shares by 25% on Jan. 7, the day the company released its estimates.

Check out the latest Roku earnings call transcript.