Two weeks ago, America barely knew who Trevor Noah was. On Monday, Comedy Central announced the South African comedian had just won one of the biggest jobs in late night television. Noah, 31, will succeed Jon Stewart as the host of "The Daily Show," a post Stewart says he will leave when his contract expires later this year.

“We are thrilled to have him,” Comedy Central President Michele Ganeless said in a statement Monday. “He has a huge international following and is poised to explode here in America.”

If the move to put a relatively unknown talent in charge of one of the network’s flagship shows seems risky, it is also a testament to how vitally important digital video has become in late night TV.

Depending on how you look at Noah, he can seem either like the best or the worst person for the job. On the one hand, he is virtually unknown in the United States, a person with fewer than a dozen appearances on American television. On the other, he is an established personality in much of the rest of the English-speaking world, a man who’s appeared on the cover of GQ magazine's South Africa edition and on stage at the Sydney Opera House.

He has 2 million Twitter followers, and his YouTube channel has more than 193,000 subscribers. Those numbers are not in the same league as Stephen Colbert’s or even James Corden’s, but they are gaudy enough, and they will come in handy in a digital battle where Comedy Central, a unit of Viacom, is losing ground.

Late Night's Second Screen

Today, the late night wars of old are being waged on our second screens, the morning after each episode airs. While ratings for late night programming as a whole have declined, clips from late night television have become one of the most popular kinds of video content on the Internet. “Of all television content, late night content seems to be the most successful [on YouTube],” said Mike Henry, the CEO of Outrigger Media, which measures and evaluates YouTube content for brands and advertisers.

Indeed, the advent of YouTube in 2005 was a huge boost for Stewart, whose clips soon enjoyed a second window of popularity and gave TV its first taste of viral distribution. Yet even with that head start, Comedy Central now finds itself badly behind. Its YouTube channel, which hosts all “Daily Show” clips along with content from the rest of its original shows, barely attracts a quarter of the 245 million monthly views that Jimmy Fallon gets, according to Outrigger data.

Executives at Comedy Central surely chose Noah because they are confident he can deliver in this format. “The future of late night is more dependent on the second screen than the first screen,” said Brad Adgate, the senior vice president of research at Horizon Media. “The network has to feel comfortable that he can put out these 5- or 6-minute clips that have become so important.”

In that regard, Noah has plenty of experience. He once had his own Internet talk show, and he’s hosted plenty of things online.

International Fame

Tapping a digitally focused, internationally known voice also reflects Comedy Central parent company Viacom's belief that television ratings are just one piece of a larger puzzle. The entertainment giant, which has been mired in a recent ratings slump, has been arguing that Nielsen ratings alone are an outdated way to measure engagement with a network’s content, saying instead that linear ratings should be regarded as just one slice of a larger pie.

The only sure thing is that "The Daily Show" is going to change, and audiences and advertisers now at least have some clue about how it might change. “'The Daily Show’ existed before Jon Stewart,” Adgate said, “and ‘The Daily Show’ will exist after Jon Stewart.”