In the third quarter, Facebook increased its monthly active users 4.7 percent from the previous quarter to 1.79 billion, topping analysts’ estimates of 1.76 billion. Daily users rose to 1.18 billion.

Facebook expanded its mobile ads business to Instagram, its photo-sharing application, which has started to contribute to the growth. While the company doesn’t break out sales, Instagram’s advertising revenue is rising faster than for Facebook’s main product, Wehner said in an interview. Still, Facebook’s main app was the bigger contributor to the sales increase, he said.

Even if Facebook’s sales gains start to slow by the middle of next year, Chief Executive Officer Mark Zuckerberg has plenty of other levers he can pull to make money. In addition to Instagram, the company has two chat apps, Messenger and WhatsApp, with more than 1 billion users each. Facebook is testing models for revenue from the properties, such as letting users talk to businesses to book trips or send flowers.

Meanwhile, Zuckerberg is changing the nature of the Facebook app to focus more on video.

“In most social apps today, a text box is still the default way we share,” Zuckerberg said. “Soon, we believe a camera will be the main way that we share.”

Eoin Treacy's view

Facebook has defied the expectations of many people, myself included, to become a genuinely innovative company that has made smart acquisitions to dominate the social media sector. Like Google/Alphabet, it might do many other things but its financial health is reliant on advertising, so monetising the active young user base of Instagram has to be high on their list of priorities. 

The share closed its overextension relative to the trend mean today and will need to demonstrate support in the current area if the medium-term uptrend is to be given the benefit of the doubt. 

Alphabet has also pulled back quite sharply this week and will need to find support in the region of the trend mean if medium-term scope for additional upside is to be given the benefit of the doubt.