Though some investors may be disappointed in Facebook's (NASDAQ:FB) slowing revenue growth, such a view could prove to be shortsighted. Sure, management expects its growth to continue to decelerate. But CEO Mark Zuckerberg was as poised as ever during the company's third-quarter earnings call as he gave investors insight into key opportunities that lie ahead of the social network.

Here are three key quotes from the call, including why management is betting big on messaging and its Stories format.

Young people using mobile devices while sitting on chairs lined up.

Image source: Getty Images.

1. Facebook's two big catalysts

Facebook's revenue growth may have come down significantly, with its third-quarter year-over-year revenue growth rate at 33% compared to 47% in the year-ago quarter, but Zuckerberg believes the company's growth story has plenty of gas in the tank. Two areas, in particular, that he believes will be meaningful catalysts are a shift in the way users are connecting and continued growth of video.

Though Zuckerberg said Facebook is positioned to benefit from these trends, he also admitted the company has some work to do to build its business around these opportunities.

For one, we're seeing the way people connect shifting to private messaging and stories. We have great products here that people love, but it will take some time for our business to catch up to our community growth. Two, we're seeing video grow dramatically across the ecosystem, and while Watch is now growing very quickly, we're well behind [Alphabet's (NASDAQ:GOOGL) (NASDAQ:GOOG)] YouTube and still working to make this a unique people-centric experience.

2. People want to connect privately

During the call, Zuckerberg went into detail about what's driving so much growth in its messaging apps and in the Stories format. It boils down to a desire to share more content privately and in a way in which the content isn't as permanent, he said.

Public sharing will always be very important, but people increasingly want to share privately too -- and that includes both to smaller audiences with messaging, and ephemerally with stories. People feel more comfortable being themselves when they know their content will only be seen by a smaller group and when their content won't stick around forever.

3. Apple: One of Facebook's biggest competitors?

Between WhatsApp and Messenger, Facebook is a juggernaut when it comes to messaging. Messages across Facebook's messaging apps now total 100 billion a day. Furthermore, Messenger's daily message volume is now greater than SMS' daily volume was at its peak.

But even with this impressive scale, Zuckerberg says Facebook faces a surprising competitor: Apple's (NASDAQ:AAPL) iMessage.

We are leading in most countries, but our biggest competitor by far is iMessage, and in important countries like the US where the iPhone is strong, Apple bundles iMessage as a default texting app, and it's still ahead. In countries where there's more competition between iOS and Android, like much of Europe, people tend to prefer our services.

Of course, Facebook has plans to compete more effectively with iMessage. The overarching strategy for growing its messaging apps, Zuckerberg said, is to make them simpler and faster and to keep adding more features. Ultimately, the more Facebook improves in these areas, the more people communicate with its messaging apps, the CEO said. Privacy and security, too, will be a big emphasis, he noted: "[W]e believe this will continue to be a competitive advantage for us."

Suzanne Frey, an executive at Alphabet, is a member of The Motley Fool's board of directors. Daniel Sparks owns shares of Apple. The Motley Fool owns shares of and recommends Alphabet (A shares), Alphabet (C shares), Apple, and Facebook. The Motley Fool has the following options: long January 2020 $150 calls on Apple, short January 2020 $155 calls on Apple, short November 2018 $155 calls on Facebook, and long November 2018 $135 puts on Facebook. The Motley Fool has a disclosure policy.