On paper it shouldn’t even be a contest. In 2007, when Facebook reached 100 million users, a new and relatively obscure video clip site called YouTube was just starting to experiment with pre-roll ads. In 2012, when Facebook boasted 618 billion daily visitors, YouTube was only just beginning to evolve from clip site to social-media platform and search engine. And in 2013, while Facebook took in a staggering $1.8 billion in ad revenue with the help of mobile ads, YouTube was still trying to decide if it was TV or Internet.

So what changed? Why are advertisers now focusing on branded digital-video content the same way they went after Facebook “likes” in 2011? Because YouTube achieved the one thing that is out of the control of every innovator, analyst, consultant and brain trust in the world—it became a cultural phenomenon. Does that mean it has now surpassed Facebook as the go-to platform for marketing dollars? Here are five arguments that say this is the case.

YouTube’s power is in the hands of the user, not an algorithm

YouTube has become the second-largest search engine in the world because it gives people the power to find the videos they want when they want. This is opposed to Facebook, which uses algorithms to determine what a user might like and then displays something similar on their feed. There are those bloggers who claim that neither YouTube nor Facebook has the edge in how videos are viewed—that there’s room for both search and curated videos. But this writer says that he’s almost never seen a curated video pop up in his FB feed that he’s wanted to see. And until Facebook can actually read people’s minds—instead of using algorithms to attempt the feat—that will remain the case. Marketers would do well to put their dollars in branded content people willfully engage with.

YouTube viewers stay longer

That’s right. As a whole, YouTube viewers have longer attention spans than Facebook users. Part of this has to do with the nature of both platforms and how visitors engage with them. Whereas Facebook users tend to watch a video clip for between 20-40 seconds, the typical length of a YouTube video is around three minutes. That means those that visit YouTube do so automatically primed to experience longer content. Marketing pros say that brands can and should take advantage of this extra time to develop more in-depth content that reaches a wider audience.

Mobile favors YouTube as well

One area where Facebook still holds sway is mobile devices. After all, everyone’s always checking their FB feed on their smartphone. But this overlooks a staggering trend among YouTube visitors—that one billion of them watch videos on their mobile devices every day. Not only that, the typical YouTube session viewed on a smartphone or tablet lasts around 40 minutes. That means while today’s generation is constantly on the go, they somehow manage to take the time to watch the equivalent of an hour-long network TV show on their handheld. Hardly an inconsequential stat. Moreover, this audience is the target demo marketers crave. According to statistics, YouTube’s mobile app reaches more 18-49 year olds than any cable channel.

YouTube is search

As mentioned above, YouTube evolved from clip site to social media platform and then ultimately to search engine. In fact, it is now the second-largest search engine in the world. That’s a lot for Facebook to compete with, since they fundamentally do not operate in the way Google operates. For marketers, this means greater power of optimization through YouTube and this will only increase over time.

YouTube has the views
To bastardize Bill Clinton’s old line, it’s the views, stupid. And YouTube’s got ‘em. By 2015 YouTube had achieved a whopping 40 billion views of branded content. Oh, and 18 billion of those views occurred in 2014 alone. This has led to certain brands, such as GoPro, successfully turning their business operation into a media juggernaut.

The intent of this piece isn’t to suggest that Facebook is now irrelevant. Indeed, they are already putting up a robust fight against YouTube in the battle for digital-video supremacy. Now users who find that perfect Facebook video can upload it to their blog without including the supporting FB post. Also, folks can sync comments from publisher’s posts to their page and vice versa. But is this enough to stop the meteoric ascension of YouTube and its quest to deliver digital-video content to an audience voracious for imagery? Only time will tell.