Susan Wojcicki, CEO of the Google-owned digital video service, announced the milestone at the VidCon digital video conference in California on Thursday, where YouTube trotted out some shiny new user metrics to aid its battle to lure advertising money away from television.

The company specifically highlighted the fact that 1.5 billion monthly viewers are also all “logged in” users, which is an important distinction as it suggests that even more viewers might be watching videos without signing into Google Accounts.

In her keynote address at VidCon, Wojcicki also noted that YouTube users watch more than an hour of mobile video on average each day. The YouTube CEO drew a direct comparison to TV, claiming that people in the U.S. spend roughly four hours per day watching television. “We think there’s lots of room to get people to watch even more YouTube,” she said in the address.

Get Data Sheet, Fortune‘s technology newsletter.

As part of YouTube’s push to earn more advertising dollars that might normally go to traditional TV networks, the company has worked hard to expand its streaming video offerings, including adding a growing number of original series to the YouTube Red subscription video service. YouTube Red has debuted 37 original series and movies to date—including new shows featuring celebrities like comedian Kevin Hart and Ellen DeGeneres announced earlier this year—and YouTube previewed 12 new series on Thursday.

The company also launched YouTube TV, its live-TV streaming service, in certain U.S. markets in April. And YouTube said on Thursday that it will be rolling out the service in several new markets soon, including Dallas-Fort Worth, Washington, D.C., and Atlanta.

YouTube’s push to further chip away at traditional TV’s advertising dollars took a hit earlier this year, when some advertisers boycotted the service after their ads showed up next to offensive material on YouTube, including videos posted by terrorist groups and white supremacists. The company apologized to advertisers earlier this year. But the fact that YouTube spent part of the Cannes Lions advertising festival this week offering details on how it is cracking down on extremist content on the site shows that the company is still trying hard to allay the concerns of nervous ad clients.

Meanwhile, YouTube is also facing increased competition on the streaming video front from other digital rivals like Hulu (which is jointly owned by the biggest TV networks) as well as social media players that have been increasingly investing in video programming. Facebook, Twitter, and Snapchat have all been adding a great deal of streaming video content and original series over the past several months.