The pressure is on Facebook after Twitter announced on Wednesday that it would ban political ads on its service.
Twitter CEO Jack Dorsey took some not-so-subtle jabs at Facebook, which recently doubled down on a controversial policy that allows candidates to lie in ads as long they pay. On Wednesday, Dorsey said that the traction political messages get on social media should be “earned” not “bought.”
“It‘s not credible for us to say: ‘We’re working hard to stop people from gaming our systems to spread misleading info, buut if someone pays us to target and force people to see their political ad…well…they can say whatever they want!’” Dorsey tweeted, taking some license with spelling and punctuating the statement with a winking emoji.
Dorsey made the announcement just minutes before Facebook announced third quarter earnings. It put Facebook executives in an awkward position as they tried to explain their side of the story with little warning.
Twitter’s move, which goes into effect Nov. 22, takes some heat from Twitter over its own political ad policy—which permitted politicians to fib—and puts it squarely on Facebook to follow suit. So far, Facebook has resisted demands by critics, politicians, and even some of its employees to fact check political ads.
For Twitter, the move is unlikely to make much of a difference financially. Ronald Josey, an analyst at JMP Securities, said that Twitter’s political ads only accounted for a few million dollars, at most, during the midterm elections—a relatively small slice of the company’s $3 billion in annual revenue.
“The reward here is much greater [than the risk],” Josey said. “That’s why Twitter is walking away from it.”
Facebook isn’t much different. In an earnings call on Wednesday, CEO Mark Zuckerberg said that ads from politicians will only account for .5% of his company’s revenue next year while he defended the decision to “protect political speech” — even if political ads don’t bring in much money.
“In a democracy, I don’t think its right for private companies to censor politicians or the news,” Zuckerberg said during the call.
He also disputed the notion that Facebook’s decision to continue accepting political ads is revenue-driven or a way to appease conservatives, who have complained that the social network is biased against them.
“We believe deeply that political speech is important, and that’s what driving us,” Zuckerberg said.
As for Twitter, analysts said that the service was never effective for advertisers in the first place. A glut of political posts, mostly unpaid, made the service too toxic for many mainstream brands.
“Clients are staying away due to the political-ness of Twitter,” Victor Anthony, an analyst at Aegis Capital, explained in a note to investors last week.
Advertisers are typically concerned about what appears near their marketing messages. Brands often have lists of subjects they don’t want their ads next to because of the risk it may drive buyers away.
Jasmine Enberg, an analyst with eMarketer, notes that even with a ban on political ads, Twitter is still rife with misinformation.
“Given the nature of the platform, people, publishers, and politicians will still use Twitter to discuss politics organically, meaning that it won’t fully solve the problem of misinformation,” she said.
More must-read stories from Fortune:
—AT&T’s CEO appeased activist investor Elliott Management
—The wireless industry needs more airwaves, but it’s going to be costly
—Spotify’s way to convert free users to paying customers: even more freebies
—Apple looks ahead to augmented reality
—Lyft tries again with monthly memberships. Here’s how much it costs
Catch up with Data Sheet, Fortune’s daily digest on the business of tech.