Shares of The Trade Desk (NASDAQ:TTD) have soared following the company's third-quarter results earlier this month. The stock has risen more than 20% since the Nov. 7 report. Zooming out further, the stock's rise is even more impressive: Shares have doubled year to date.

But with the stock rising so sharply recently, expectations for the underlying business are sky high. Will The Trade Desk be able to deliver more strong business growth in 2020 and beyond? A closer look at the digital advertising platform specialist's key catalysts suggest there's still room for more robust growth. Two growth drivers, in particular, look poised to contribute meaningfully to The Trade Desk's growth story in 2020: Connected TV and audio.

Here's a look at these two key catalysts.

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Image source: Getty Images.

CTV

As usual, advertiser ad spend on mobile channels played a key role in The Trade Desk's impressive third-quarter results, which featured a 38% year-over-year revenue increase. Accounting for 48% of the quarter's total revenue, mobile was driven by a 48% year-over-year increase in mobile video ad spend and a 58% jump in mobile in-app add spend.

But connected TV (CTV) not only continued to grow at a faster rate, up 145% year over year during the quarter, but also seemed to be the channel that The Trade Desk CEO Jeff Green remains most excited about.

"Connected TV is undergoing a once in a generation shift from linear to digital. Advertisers and publishers are realizing the benefit coming from the emerging digital video landscape," Green said in a statement to The Motley Fool. The CEO noted that major players in the streaming space, "including Disney, Amazon, Channel 4, TF1, and more have realized the opportunity and are working in conjunction with us -- and our supply side partners -- to monetize that content."

Even more, this shifting of advertiser budgets from linear TV to digital is occurring at a unique time of opportunity, with 2020 set to include the election cycle, the summer Olympics, and the continued rollout of live sports on CTV, Green explained.

Audio

While CTV may represent The Trade Desk's biggest opportunity, investors shouldn't overlook skyrocketing ad spend in audio. Ad spend on The Trade Desk's platform for audio programmatic advertising jumped 160% year over year in Q3.

"For our customers, it's an incredibly attractive channel because it delivers high-performance metrics such as completion rates," Green told The Motley Fool. "Advertisers want to get in front of this highly engaged audience."

Particularly attractive channels within audio include the fast-growing streaming music and podcasting markets.

Despite these notable catalysts for the tech company in 2020, investors should tread carefully. A $10 billion-plus market capitalization on just $100 million in net income means The Trade Desk will have to continue executing and growing at torrid rates to live up to this valuation. But based on the company's consistent market share gains and rapid growth since its IPO, it wouldn't be surprising to see The Trade Desk meet -- or even exceed -- high expectations in the years to come.