Worldwide, people are watching more than 1 billion hours a day of YouTube videos, a number that threatens to topple the primacy of U.S. television viewing. That represents a 10-fold increase in YouTube viewership since 2012, said to be pegged, in part, to Google’s use of artificial intelligence to recommend videos. These personalized video line-ups keep people watching, and YouTube’s exponential growth of content — 400 hours of video uploaded each minute — means there’s always something new to watch.

The Wall Street Journal quotes YouTube chief product officer Neal Mohan as saying that, “the corpus of content continues to get richer and richer by the minute, and machine-learning algorithms do a better and better job of surfacing the content that an individual user likes.”

According to Nielsen data, Americans watch “roughly 1.25 billion hours of live and recorded TV’ daily. At 1 billion monthly users in 2013, YouTube is most likely now larger than China Central Television, the world’s biggest TV network, with more than 1.2 billion viewers.

Although YouTube reportedly took in $4 billion in revenue in 2014, breaking even, chief executive Susan Wojcicki stressed that, “growth is the priority.” That goal is aided by parent company Google, which, says StatCounter, handles about 93 percent of all Internet searches. According to Strategy Analytics, Google embeds YouTube videos in search results and pre-installs the YouTube app on its Android software, the operating software of 88 percent of smartphones.

Not everyone is pleased with how YouTube has shaped “media consumption into narrow categories of interests.”

“If I only watch heavy-metal videos, of course it’s serving me more of those,” said Northeastern University computer science professor Christo Wilson. “But then I’m missing out on the diversity of culture that exists. The blessing and curse of cable and broadcast TV is it was a shared experience… But that goes away if we each have personalized ecosystems.”

Elsewhere, WSJ reports that Comcast struck a deal with YouTube to let its subscribers with the latest X1 set-top box (about half its install base) to watch YouTube videos. Comcast struck a similar deal last July with Netflix. With the X1 STB, users will be able to search for YouTube videos (along with Netflix content and traditional TV fare) with its voice-controlled remote.

In recent years, to head off rivals, cable companies have sought to create more integration with online content companies, saying “encouraging online video consumption makes consumers value their broadband products more.” For YouTube, the deal may draw in more subscribers to YouTube Red , which has struggled to grow.