After reporting huge growth in its fourth quarter last month, Facebook (NASDAQ:FB) investors are now looking forward. In order to justify the stock's price-to-earnings ratio of 77, they have big expectations. Can the company live up to the market's optimistic outlook? To get a better idea of how CEO Mark Zuckerberg is thinking about the future, here are some quotes from the social network's most recent earnings call.

Zuckerberg Facebook

Facebook CEO Mark Zuckerberg (right). Image source: Facebook.

On improving lives
"But it's also important to consider not just our business results but how we're improving the lives of people and communities around the world," Zuckerberg said after noting the company's revenue for Q4 soared 52% year over year to over $5.8 billion.

While this reference to improving lives around the world may seem cliche, this big vision is what makes Facebook the company it is. Indeed, it's Zuckerberg's passion for connecting the rest of the world that has him striving to grow its user base from 1.6 billion to a whopping 5 billion monthly active users.

The path to monetization of Facebook's younger platforms
At what point can investors begin to expect Facebook to begin to turn its younger platforms, such as WhatsApp and Messenger, into businesses in their own right? Zuckerberg provided a useful road map for investors to think about Facebook's plans for these platforms.

And we have a formula for how we build these businesses. First, you build a great consumer experience, right, that helps people share in a new way that's really important. Then, after that, you can start to introduce organic ways that people can interact with businesses. ... Not necessarily ads, but organic interactions around not necessarily just your friends and families, but more public figures and businesses. And then only once you have that ramped up to a good, to a good scale can you really start dialing up advertising, having that feel good and be a good part of the experience with good content because all of those public figures and businesses are already participating in the platform at scale.

On Instagram, Zuckerberg said the company is already in the process of turning organic interactions between businesses, public figures, and users into a monetized experience. For WhatsApp and Messenger, he said investors are "going to see the same playbook... in terms of making it so there are organic businesses and public figures."

So, investors should expect the company's playbook for these interactions in its messaging service to become increasingly clear throughout 2016.

The new "Like" button is coming
Last year, Facebook began testing a new "Like" button called Reactions. Investors can expect this new button to roll out to not just Facebook but across all of the company's platforms, according to Zuckerberg.

New Facebook Like Button

Reactions. Image source: Facebook.

So Reactions is going to roll out on every platform. We're testing it in a handful of countries to start, just to make sure that we have the UI and interaction simple enough that people could express more of what they wanted without getting in their way. ... And so far, I think there are a few tweaks that we needed to make to Reactions since initially testing it, but it's going well and I think we plan to roll it out everywhere pretty soon.

The new button is significantly different form its predecessor. In addition to the traditional "Like" button, Reactions will feature a range of emotions, which are expressed in emojis, for users to choose from when engaging with posts across the companies' platforms.

This will be a critical year for Facebook. The company will need to continue to grow its business rapidly in order to live up to its premium valuation, and investors will be looking for the social network's younger platforms to begin to show signs that they are maturing into solid businesses.

Daniel Sparks has no position in any stocks mentioned. The Motley Fool owns shares of and recommends Facebook. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.