Source: Facebookbrand.com

More than 800 million people access Facebook (META -10.56%) over a mobile device every single day, and the company says its family of mobile apps now consume more than 20% of the time Americans spend on their smartphones.

Indeed, young people are now just as likely to use their phone to access a social app, like Facebook or Messenger, as they are to make a phone call.

It's not a stretch to say that Facebook has quickly emerged as the dominant player in mobile. Investors are seeing this trend play out in the company's earnings -- and ultimately, in its stock price.

Fast rise in mobile
Mobile ad revenue was up 74% year over year last quarter. It now makes up some 76% of the company's $3.8 billion in quarterly ad revenue. Considering that just a little more than three years ago Facebook generated exactly zero dollars from mobile, the growth of its mobile advertising platform has been impressive.

And with the development of Messenger as a stand-alone app, Instagram, and WhatsApp, Facebook should only strengthen its hold on this crucial front. That's a promising sign for Facebook investors who are in it for the long haul.

Infographic: Where Facebook's Revenue Growth Comes From | Statista
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Ignore the dip
It can be easy to get caught up in a stock's gyrations, especially around the time the company reports its earnings. But often, those short-term movements have little to do with a company's long-term picture, and as buy-to-hold investors, the latter is what's really important.

There are few better examples of that right now than Facebook, which reported remarkable revenue growth July 29, only to see its stock drop from a pre-release closing price of $96.99 to a next-day low of $91.80.

Short-term traders are worried about the company's costs as it builds out its apps and advertising platforms, as well as its much-anticipated venture into virtual reality, but long-term investors can take solace in a number of things, including fast revenue growth and a membership base that continues to defy the odds and expand despite its seemingly ubiquitous presence.

And perhaps most important is the company's impressive dominance of mobile computing.

More than 1.3 billion people use Facebook on a smartphone or tablet each month now, the company reports. And more than 800 million of those people use Facebook apps on their mobile devices every single day.

Smartphone revolution
CEO Mark Zuckerberg said the company has three priorities moving forward, and the first of those is "capitalizing on the shift to mobile." It can capitalize because Facebook knows mobile is its domain. "Mobile remains the key driver of our growth," Facebook CFO David Wehner said in the most recent earnings call.

Nearly two-thirds of Facebook's monthly average users use the platform every day, the company says. And users spend an average of 46 minutes a day on Facebook sites and apps.

A big part of that stickiness is mobile. If users have a product they enjoy using on their smartphone -- which they have on them at all times -- they are far more likely to check in often.

Nearly two-thirds of Americans own a smartphone -- a number that has nearly doubled over just a four-year stretch, according to a study by Pew Internet Research. Even more telling of how far the mobile revolution has advanced in just a short time: Nearly one in five Americans now rely to some degree on a smartphone for Internet access.

Of all smartphone users, more than two-thirds in the Pew study reported using their phones for consuming news and for posting their own news along with photos and videos to social media. And when you break down that use into age segments, you see that 91% of smartphone users in the 18-29 bracket used their phone for social networking, nearly the same number -- 93% -- as those who used their devices to actually talk.

That's the opportunity Facebook has to capitalize on.

More to come
Perhaps even more important, the company is still in the very early stages of monetizing two of its more mobile-specific apps, Messenger and WhatsApp. Zuckerberg has indicated Facebook plans to take a slow approach to monetizing these, working first to establish a very strong product for the user, and then to figure out what types of advertising the apps will offer to businesses.

That may mean slower revenue growth in the short term, but it makes for an extended runway for growth in the longer term.