Facebook has had plenty of hot-water moments in the year since its CEO Mark Zuckerberg testified before Congress on the platform's data and privacy troubles.
But advertisers just can't seem to quit Facebook.
2018 was chock-full of scandal for Facebook, from the discovery that British political consulting firm Cambridge Analytica had exploited the platform to collect data of more than 50 million users without their permission, to media reports that detailed Facebook's efforts to control public dialogue around its numerous problems, including its relationship with a Washington-based opposition research firm.
But for all the noise, Facebook's ad revenue share and user base keep growing. So far, advertisers haven't found alternatives that give the same kind of bang for their buck.
In 2018, the company's total ad revenue grew 38% to $55 billion, the company said on its fourth-quarter earnings call, and net digital ad revenue in the U.S. grew 36% to $23.66 billion, according to Feb. 2019 data from eMarketer.
The company's share of ad revenue is growing, too. Facebook's net digital ad revenue share in the U.S. grew from 19.8% in 2017 to 21.8% in 2018, and was expected to reach 22.9% by 2021. Meanwhile, Google's net digital ad revenue share in the U.S. shrank from 39.6% in 2017 to 38.2% in 2018, according to eMarketer.
Advertisers keep spending because, despite all the negative publicity and calls to boycott the service, users are sticking around: Facebook's monthly active users grew 9 percent to 2.32 billion in 2018.
With Facebook's level of reach, "It just makes sense to always recommend that to our clients," says Shuman Sahu, director of performance media at performance digital marketing agency Nina Hale. "We definitely don't exclude Facebook because of the scrutiny they've gone through."
Tom Buontempo, president of social media agency Attention, says any outrage around Facebook's scandals has been short-lived. If anything, brands are often spending more on Facebook, he said.
"More of our clients are spending more across the Facebook ecosystem," he says. "There aren't a lot of options right now." He says it's tough for brands to get the same kind of return for their money as they do on Facebook. And though Amazon has emerged as a big contender, it hasn't stung the Facebook ecosystem in terms of spend, he said.
GroupM's global president of business intelligence Brian Wieser says it would take a brand believing their reputation could be hurt to make meaningful changes.
"The real thing that would cause a brand to slow spending is if they thought their brand would be tarnished," he said.
That's a lot less likely to happen with Facebook than with Google's YouTube, for example, where a brand's ad could appear directly on a video containing disturbing content. For Facebook, any issues "don't stick to the brands — yet," he said.
"Individual advertisers can be concerned about all of these things and they're very alert to these things now in ways they weren't two years ago -- that doesn't mean they're changing what they're doing," he said. "They're just very, very aware and very mindful that things could get much worse for them in terms of their association."
There have been some defectors. A number of companies told CNBC earlier this month they had stopped advertising with Facebook and Instagram following data and privacy scandals. They include Firefox browser creator Mozilla, which said it wouldn't return to Facebook until there were "significant and systemic changes in the way Facebook treats its customers."
Meanwhile, some brands are more amenable to trying out advertising on other platforms.
George Popstefanov, founder and CEO of digital agency PMG, said the agency has seen clients who have pulled away from Facebook, and some that have begun testing other platforms like Pinterest, Twitter or Snapchat.
"I think the testimony has brought privacy and targeting to the forefront even more so than before," he said.
Nina Hale's vice president of media Kathleen Petersen added the agency hasn't seen changes in the role that Facebook plays in its marketing mixes or in the amount of investment brands are putting behind it. But the agency has seen differences in some limitations Facebook has put on advertiser targeting. In March, for instance, Facebook said it would be overhauling ad targeting for housing, credit and employment ads so they can't be used to discriminate on the basis of race and ethnicity, gender and other legally protected categories in the U.S.
That means advertisers have had to work a little harder to reach the right consumers for a particular ad.
"At this point as marketers and advertisers, we have to get more creative," Sahu said, adding that advertisers need to use their knowledge of consumers and apply it to user behavior or intent-based targeting instead of simply plugging in who an advertisement should be targeted to.
For instance, instead of serving an ad specifically to people who make more than $100,000 a year, the advertiser might target users in the top 10% of zip codes by average household income who also show an interest in luxury goods.
"You have to get a little smarter about the targeting," he said.
If there's any event that could drive advertisers away from Facebook, Sahu said, it wouldn't be bad press around a new privacy scandal. Rather, he believes advertisers would leave only if brands can no longer target the consumers they want to reach.
"It's going to take a lot to take down a behemoth like Facebook," he said.