A key metric always under the microscope: average revenue per user. Third-quarter ARPU was $1.72 worldwide, up from $1.60 in the prior quarter and up from $1.29 a year earlier. A year ago average revenue per user grew 19 percent sequentially. It's unlikely to grow as fast this quarter, but that growth is key.
Facebook has been struggling with the fact that its ability to make money overseas has far lagged the U.S.—we'll see how fast it can grow that international revenue to catch up.
Mobile will also be in the spotlight. In the third quarter mobile accounted for 49 percent of Facebook's advertising revenue, and the company reported 507 million mobile daily active users and a 45 percent increase in monthly active users to 874 million.
This quarter that mobile monthly active user number is expected to jump to 925 million or more. Sterne Agee analyst Arvind Bhatia projects mobile ad revenue will be up 25 percent from the prior quarter and will represent 52 percent of the company's ad revenue. "The shift from desktop to mobile advertising appears to be happening at a faster pace than was expected even three or six months ago," Bhatia says.
Looking forward, JPMorgan's Anmuth projects Facebook's mobile ads will account for 63 percent of total ad revenue in 2014. Anmuth is bullish about Facebook's mobile ad potential, saying advertiser demand and ad quality should "more than offset" slower increases in Facebook's ad load, which will in turn drive higher click-through rates and ultimately greater ad quantity over time.
Instagram is another hot topic, with the photo- and video-oriented social network starting to roll out ads on Nov. 1. The early results have been positive—Anmuth cites Levi's reaching 7.4 million 18- to 49-year-olds in nine days. The question now—how many users does Instagram have, and will other advertisers getting on board?
Video ads are expected to be a key catalyst for 2014 growth. Facebook has been taking its time rolling them out broadly to make sure they don't turn off users. Cowen analyst John Blackledge forecasts $1 billion in video advertising for the social media network in 2014.
Further, Sterne Agee's Bhatia predicts video ads will be the silver bullet to help Facebook tackle the $200 billion worldwide TV ad market, projecting video ads to comprise as much as 10 percent of Facebook's ad dollars this year.
—By CNBC's Julia Boorstin. Follow her on Twitter: @JBoorstin.