With Roku (ROKU -10.47%) shares down about 30% from the high they hit earlier this year, it's a great time to take a look at the stock and attempt to gauge whether its recent drubbing has gone too far.

The video streaming platform company is just one among many growth stocks to get battered in 2021 -- particularly those that soared most enthusiastically in 2020. Investors seem to be reevaluating whether or not these stocks were worth the significant premiums they garnered in last year's run-up.

A closer look at the Roku reveals some incredible momentum and opportunities, suggesting that now may be a great time for investors to get in on this growth story.

Here are three major catalysts for Roku stock.

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Image source: Getty Images.

1. The $70 billion U.S. TV advertising market

Though Roku stock often experiences volatility based on headlines about competing streaming platforms like Alphabet's Android TV and Amazon's Fire TV, management frequently reminds investors that the market it's most focused on is not the share these streaming platforms garner -- it's the $70 billion pie of annual U.S. TV advertising spending, as well as the $160 billion market for global TV advertising. 

In 2020, only about $8 billion was spent on streaming TV ads in the U.S. even though viewers are rapidly shifting their attention to streaming services. By 2024, that metric is expected to grow to more than $18 billion, according to estimates by eMarketer. 

Roku's strategic focus on capturing a share of this massive market is working. In the first quarter, total streaming ad impressions delivered on the Roku platform more than tripled year over year, helping platform revenue (sales primarily from Roku's take rate on ads delivered on its platform and its share of third-party subscriptions) grow by 101% year over year. 

2. The Roku Channel

One way Roku is helping promote the services on its platform and capitalize on the rapidly growing demand for streaming-TV ads is by investing aggressively in The Roku Channel -- a streaming service that aggregates other services' content and Roku's own licensed content and exclusives into one seamless experience.

The Roku Channel has seen explosive growth, with subscriptions to third-party services within it more than doubling year over year, and viewership for these subscription services "growing more than twice as fast as the corresponding DTC apps on the Roku platform," the company said in its first-quarter shareholder letter.

At the end of Q1, The Roku Channel had an audience of approximately 70 million people, up from 63 million just three months earlier. On a year-over-year basis, both account reach and streaming hours for The Roku Channel grew twice as fast as these metrics did for the overall Roku platform.

Management contends that The Roku Channel's momentum demonstrates its flywheel: "easy access to content with broad appeal attracts viewers, that viewer engagement attracts advertisers, and advertiser spend in turn allows us to invest in more content."

"This flywheel is enabling us to be more creative and expansive in sourcing content suited to an AVOD (advertising video on demand) business model," Roku management explained in its first-quarter shareholder letter, "and we expect that our content investment will continue to be commensurate with the scale and growth trajectory of The Roku Channel."

3. New streaming TV services

Last, it's worth noting that the aggressive investment in connected TV -- from both streaming-first companies and traditional media companies that are finally making the shift to streaming -- is validating Roku's positioning.

Roku management often says its business is predicated on the belief that all TV will eventually be streamed. To capitalize on this, the company aims to be the Switzerland of connected TV -- a neutral player that every service wants and needs to be on. It's not surprising, therefore, that Roku has specifically called out the launch of new services as a key catalyst for its business.

"We also benefited from the launch of multiple premium DTC services in the second half of 2020," management recently said. 

It's a beautiful position to be in: The more investment there is in connected TV, the more Roku is likely to benefit.

Given the company's strong momentum and its positioning at the center of a major growth trend with a huge addressable market, Roku's recent share price pullback may be a great buying opportunity for investors willing to hold the stock for the long haul.