As Facebook's (META -1.38%) stock price continues to flirt with all-time time highs, it's easy to see why some investors might be a bit wary. After all, Facebook is trading at a premium, right? At least based on historical valuations. Facebook bulls need only look as far as last quarter's earnings report to validate its nice stock price run. With the release of Q3 earnings on tap for next week, Facebook shareholders will likely see more of the same.

The beauty of Facebook for long-term investors goes beyond 2014's results. As remarkable as its run has been, what makes it even more extraordinary is Facebook hasn't even tapped into several revenue drivers, while others are just getting off the ground. Small businesses, the focus of Facebook's recent "Fit" workshops are just beginning to make an impact on revenues, and the multiple acquisitions the company has made so far this year are sitting on the shelf, just waiting to kick-start future growth. But there's one area in particular that once it gets up-and-running, could trump all of Facebook's other growth opportunities, pushing its share price to $100.

Not just any mobile
There were several stellar aspects of Facebook's Q2 earnings announcement, including growing its monthly average users, or MAUs, to a whopping 1.32 billion, a 61% increase in revenues compared to last year, and improved margins that are the envy of even digital ad king Google (GOOG 1.44%) (GOOGL 1.89%). All heady stuff, and reasons that Facebook's stock price is close to breaking through some resistance to hit all-time highs.

But the icing on Facebook's cake last quarter, and will almost certainly be the case going forward, was its mobile advertising revenues, which represented about 62% of its $2.68 billion in ad sales. Facebook CEO Mark Zuckerberg has been laser-focused on mobile usage and advertising for the last couple of years, and it's paying off in a big way. And if recent data from eMarketer is any indication, Facebook's mobile emphasis, combined with its pending video advertising initiative, is primed to jump-start the path to $100 a share.

According to eMarketer, digital video ads viewed by smartphone users are easily the most effective means of turning consumers into customers. Tablets and PCs are a distant second and third, respectively. Of smartphone users who took the time to view a video ad, 64% of those "highly attentive" consumers said they intended to purchase the product or service advertised. That compares to 56% of tablet users and 52% of old-school PC folks.

Facebook's ad targeting capabilities that utilize its reams of user data combined with internal algorithms are unmatched by Google, or any other digital advertiser. That's why Facebook is able to charge a reported $1 million a day for simply testing video ads on its site, something we should see rolled out en masse by next year, if not sooner. It's clear from eMarketer's report that smartphone users will act on video ads of interest and that, combined with Facebook's ability to match the right spot to each individual, will boost its mobile ad results even further: and that's saying something.

Google gets mobile video, too
Not surprisingly, Google understands the opportunity that mobile ads represent -- nearly $33 billion this year alone -- and it stands to reason video spots will represent a larger and larger piece of its revenues going forward. While Google already garners a healthy amount of ad revenue from mobile devices, that's primarily from its cost-per-click, or CPC, revenues, which tend to be lower on mobile, and have steadily declined over the last couple of years.

That's why so many industry pundits are focused on Google's YouTube video property, which is already becoming a significant source of ad revenue. Though Google doesn't provide specifics, most estimates suggest it's generating about $4 billion annually. No way to tell how much of YouTube's estimated video ad revenue is driven from smartphone owners, but as eMarketer's report indicates, the results will keep advertisers coming back for more.

Final Foolish thoughts
With multiple ways to drive future growth, don't be surprised to see Facebook hit $100 a share as early as next year. On top of the aforementioned list of growth drivers, monetizing Instagram, particularly utilizing video ads, could prove to be a huge source of revenue. But mobile video ads, especially when viewed by smartphone users, will go a long way toward solidifying Facebook's spot as the king of mobile advertising. Why? Because it works, and Facebook shareholders will reap the rewards.