This column has been updated from Oct. 12 to contain up-to-date analyst estimates.

Will Facebook Inc. (FB) - Get Facebook, Inc. Class A Report  be able to continue its long string of sales and earnings beats when it reports on earnings after the close this Wednesday? 

That's the billion-dollar question for the world's largest social network, whose shares are up more than 50% this year and whose current market cap stands at $521 billion. The consensus is for revenue of $9.85 billion (up 41%) and GAAP EPS of $1.28.

TheStreet will be hosting a live blog analyzing Facebook's third quarter earnings report and investor call after the market close on Thursday. Please check our home page for more details.

Here are four key things to watch: 

1. Ad sales growth, and where it's headed

Facebook's ad sales, which account for the lion's share of its revenue, rose 47% in Q2 to $9.16 billion, a rate not far removed from Q1's 51% and Q4 2016's 53%. The second-quarter growth was driven by a 19% increase in the number of ad impressions for which Facebook recorded revenue, and a 24% increase in average price per ad.

Management has been warning for a while that ad growth will be pressured starting in the second half of 2017 because there will no longer be major increases in ad load (the number of ads Facebook shows over a given amount of viewing time) for its core news feed. The company still has other levers to grow ad sales, such as user growth, higher ad prices, Instagram and the company's Watch video platform (and further down the line, Messenger and WhatsApp). But the impact of diminishing ad load growth certainly bears watching. The consensus is for ad revenue to grow 42% in Q3 to $9.71 billion.

2. Daily active users (DAUs)

Daily active users for Facebook's core platform and Messenger rose 3% sequentially and 17% annually in Q2 to 1.33 billion. Though those are impressive numbers for a company of Facebook's size, sequential DAU growth trailed the 4% sequential growth seen in monthly active users (MAUs), after many quarters of outpacing MAU growth. That points to slightly lower per-user engagement.

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The Q3 report should provide us with a better idea of whether this was a one-time blip, or something to be more concerned about. From the looks of things, Facebook has been getting more aggressive about sending notifications to users in an attempt to get them to visit its site and apps more often.

Facebook CEO Mark Zuckerberg recently said that he'd consider using cryptocurrency and encryption as safety tools on the platform.

3. Spending guidance

In July, investors cheered Facebook's cutting of its annual spending guidance: The company now forecasts 40% to 45% GAAP cost and expense growth (adjusted from prior forecasts of 40% to 50%), and predicted its capital spending would be at the low end of a $7 billion to $7.5 billion guidance range.

Much like Amazon Inc. (AMZN) - Get, Inc. Report , markets have signaled that they trust Facebook to make big investments wisely. Nonetheless, there will likely be another positive reaction if Facebook once more cuts its spending plans.

4. Ad product commentary

Mark Zuckerberg mentioned on Facebook's Q2 earnings call that he wants his company to speed up the pace at which it monetizes its messaging apps. Look for analysts to press management once more on what they're planning. Any commentary given about Facebook's efforts to grow video ad sales will also be closely watched, particularly given reports of early issues with the mid-stream video ads it has begun running against professional content.

This column has been updated from Oct. 12 to contain up-to-date consensus estimates.

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Facebook won't be the only company reporting after the bell. Here's what to expect from GoPro (GPRO) - Get GoPro, Inc. Class A Report :

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