For the past decade, YouTube has been the default home for video on the Web. But that stronghold is quickly being challenged, with new competition from Snapchat, Spotify and Vessel. Most formidably, Facebook has become a legitimate challenger by reaching four billion video views per day in a little over a year since starting.

Video views on YouTube are different from video views on Facebook (FB), Wojcicki said. On YouTube, users specifically click to watch clips while, on Facebook, they play automatically.

“We want our users to engage. We want them to not be channel surfing,” she said. “We want them to say, ‘I saw a video, I cared about that video, I commented on that video, and I continued watching it.'”

Ultimately Wojcicki believes online video is growing fast enough for all the new entrants to thrive. “Facebook, Twitter, and everyone has recognized it as a big opportunity and they’re coming into the market,” she said. “I don’t think that’s a surprise because of the size of the opportunity.”

Does YouTube, which is owned by Google (GOOG) need to react to all the new entrants? The company has a big pipeline of projects, Wojcicki noted. (The company is focused on “mobile, mobile, mobile,” she later said.)

Wojicki, who has spent her career at Google as its 16th employee, noted that YouTube’s growth is accelerating. “Overall I feel pretty encouraged.”