YouTube is mainly a 3-way market; the content producer, the content consumer and the ad seller. All of which benefit from network effects. In addition to that,

YouTube is mainly a 3-way market; the content producer, the content consumer and the ad seller. All of which benefit from network effects. In addition to that, a high 7 day active user count is a very attractive goal in itself as you can upsell them almost anything adjacent. Eg. Premium subscription, music service, movies, tv channels...