Facebook (NASDAQ:FB) had an impressive 2019, with shares rising 54%. Investors applauded the company's strong growth in revenue and active users. Can the social network keep growing its top line and its user base in 2020?

Investors will get a timely update on Facebook to see how well the company is doing and to hear commentary from management on its expectations for 2020 when the company reports earnings later this month. Facebook is scheduled to report its fourth-quarter and full-year results on Jan. 29. 

Ahead of Facebook's fourth-quarter update, here's a look at some key areas to watch.

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Image source: Facebook.

Revenue growth

Despite Facebook management's implication at the beginning of the year that its top-line growth could face headwinds during the year, revenue growth actually accelerated. After reporting a year-over-year revenue growth rate of 26% in Q1, total revenue grew by 28% and 29% in Q2 and Q3, respectively.

But management is still insisting that its top line can come under pressure. "We expect our Q4 reported revenue growth rate will decelerate by mid to high single-digit percentage compared to our Q3 rate," explained Facebook CFO Dave Wehner in the company's third-quarter earnings call. "This deceleration is largely driven by the lapping of several successful product optimizations in Q4 of last year, as well as ad targeting related headwinds."

In other words, management forecast fourth-quarter revenue to decelerate to a year-over-year growth rate of about 20% to 24% in Q4. Notably, the consensus analyst forecast currently calls for revenue growth of 23.3%.

User growth

Another area Facebook has fared very well in 2020 is with user growth. The company has added approximately 200 million unique daily users across its family of apps, including Facebook, Instagram, Messenger, and WhatsApp, bringing total unique daily users to 2.2 billion. This metric, which Facebook refers to as a "family metric," attempts to de-duplicate users across its services so that one user is only counted for once, even if they are a daily user on multiple Facebook-owned social networks.

Investors should look to see if these unique daily users across Facebook's family of apps increased further in Q4.

Guidance

Finally, investors will want to look for updated commentary from management on its expectations for 2020.

Management said in Facebook's 2020 earnings call that it expects total 2020 expenses to be between $54 and $59 billion, up from an estimated $46 to $48 billion in 2020. This uptick in expenses, Facebook says, will be due to a reacceleration in hiring and marketing spend. Further, management said it expects revenue growth to decelerate in 2020, albeit at a much more moderate rate than the deceleration management said it expects in Q4.

Investors can tune into Facebook's fourth-quarter update after the market closes on Wednesday, Jan. 29.