The company's live YouTube TV service fared relatively well, too, with about 2 million subscribers by the end of 2019. That makes it smaller than Hulu With Live TV's estimated 2.7 million from November and Sling TV's 2.69 million. However, that's still a healthy number for a service that was comparatively late to the party.

While YouTube hasn't elaborated on just how its services reached these milestones, there are a number of possible factors at work. YouTube's ubiquity gives it a lot of exposure. It's not a stretch to sign up for YouTube Music if it's just a short hop away on your Android phone, and you're going to get pitches for Premium and TV simply by visiting YouTube. And then there's sponsorships -- watch the right MLB games and other events and it'll be hard to avoid marketing for YouTube TV. If there's a challenge for YouTube, it's competing with rivals on sheer numbers.