Google’s/Alphabet’s 16th quarter as a publicly traded company came in Q3 2008. Facebook just passed that milestone at the end of June. I’ve been fascinated at just how each of them has grown top-line revenues. Their results over this time span have been eerily similar, with Facebook demonstrating more pronounced seasonality in Q4 than its search rival. You can see that in the graph above for 2Q, 6Q, 10Q and 14Q.

Now take a look at the most recent quarter. It looks like Christmas came early for Facebook. Its sharp Q/Q increase looks like the kind we usually see in Q4, and while Q2 did include Easter, Mother’s Day and what marketers call “Dads and Grads,” the lift is so much more pronounced, and off a larger base, than in previous Q2s.

What’s going on?

There are two primary factors that have accelerated Facebook’s recent growth, relative to Google’s. The first is widespread global smartphone adoption. According to Statista, global annual smartphone shipments first exceeded 1 billion in 2013. With 2016 forecasts of 1.5 billion, it will take the market just three years to grow by 50 percent. Meanwhile, smartphone users spend a whopping one out of every five mobile minutes on Facebook. That basically means that the social giant has captured an out-sized portion of the largest market of computing devices the world has ever seen.

Now think back to the years between 2003 and 2008, in which we find Google’s/Alphabet’s first 16 quarters. The PC market was king. In 2005, vendors shipped over 200 million units, and over 900 million were in use worldwide. The smartphone market in the U.S. didn’t exist, arguably, until Apple’s App Store for the iPhone debuted in 2008. If you wanted a smartphone, you had go to Europe or Japan.

Google therefore got to be, well, Google on the strength of PC-based searches through the century’s first decade, but the PC market was (and remains) a much, much smaller one than the one for smartphones. Remember: in 2016, smartphone vendors will ship more than 50 percent more new devices than the combined number of global PC users in 2005. Addressable market, therefore, has given Facebook a huge edge.

There’s another reason why Facebook’s growth is accelerating: it gives marketers the best combination of scale and targeting, especially on mobile devices.

Facebook has something for marketers of every stripe. If you’re a brand marketer with lots of video and the need to buy impressions, Facebook can help you do that. If you’re a performance marketer looking to retarget consumers who have visited your website or abandoned a shopping cart, Facebook can get that done, too. Marketers and agencies know they have to move more of their branding and performance dollars to mobile. Facebook offers them a powerful way to do just that.

There are other social networks with attractive advertising options for marketers. None of them can match Facebook’s global reach yet, though. Many are still trying to find the right combination of ad products, targeting options and measurement capabilities for their audiences.

Smartphones, and what Facebook allows marketers and users to do on them, explains why Facebook took a great leap forward in Q2 2016.