Twitter will begin removing tens of millions of suspicious accounts from users’ followers Thursday, signaling a major new effort to restore trust on the popular but embattled platform.

The reform takes aim at a pervasive form of social media fraud. Many users have inflated their followers on Twitter or other services with automated or fake accounts, buying the appearance of social influence to bolster their political activism, business endeavors or entertainment careers.

Twitter’s decision will have an immediate effect: Beginning Thursday, many users, including those who have bought fake followers and any others who are followed by suspicious accounts, will see their follower numbers fall. While Twitter declined to provide an exact number of affected users, the company said it would strip tens of millions of questionable accounts from users’ followers. The move would reduce the total combined follower count on Twitter by about 6 percent — a substantial drop.

An investigation by the New York Times in January demonstrated that just one small Florida company sold fake followers and other social media engagement to hundreds of thousands of users around the world, including politicians, models, actors and authors. The revelations prompted investigations in at least two states and calls in Congress for intervention by the Federal Trade Commission. In interviews this week, Twitter executives said that the Times’ reporting pushed them to look more closely at steps the company could take to clamp down on the market for fakes, which is fueled in part by the growing political and commercial value of a widely followed Twitter account.

Officials at Twitter acknowledged that easy access to fake followers, and the company’s slowness in responding to the problem, had devalued the influence accumulated by legitimate users, sowing suspicion around those who quickly attained a broad following.

“We don’t want to incentivize the purchase of followers and fake accounts to artificially inflate follower counts, because it’s not an accurate measure of someone’s influence on the platform or influence in the world,” said Del Harvey, Twitter’s vice president for trust and safety. “We think it’s a really important and meaningful metric, and we want people to have confidence that these are engaged users that are following other accounts.”

The market for fakes was also hurting Twitter with advertisers, which increasingly rely on social media “influencers” — mini-celebrities who promote brands and products to their followers — to reach customers. In recent months, advertising and marketing firms have put pressure on Twitter, YouTube and other platforms to help ensure that influencers have the reach they claim. Last month, the consumer goods giant Unilever, which spends billions of dollars a year on advertising, announced that it would no longer pay influencers who purchased followers and would prioritize spending advertising dollars on platforms that took steps to stamp out fraud.

In an interview Tuesday, Unilever’s chief marketing officer, Keith Weed, praised Twitter for its decision.

“People will believe more and read more on Twitter if they know there is less bot activity and more human activity,” Weed said. “I would encourage and ask others to follow.”

For Twitter, the reform comes at a critical moment. Though it is a smaller company with far fewer users than Facebook or Google, Twitter has been sharply criticized for allowing abuse and hate speech to flourish on its platform. And along with other social networks, Twitter was a critical tool for Russian influence during the 2016 election, when tens of thousands of accounts were used to spread propaganda and disinformation. Those troubles dampened Twitter’s prospects for acquisition by a bigger firm, and the company, which went public in 2013, did not turn a profit until the final quarter of last year.

In recent months, Twitter has taken a number of steps to improve what Harvey and other company officials call “healthy conversation” on the platform, including rooting out fake and automated accounts. Last month, Twitter announced that as of May, its systems were “locking” almost 10 million suspicious accounts per week, far more than last year, and removing more for violating anti-spam policies.

Twitter locks an account — blocking it from posting or interacting with other users — when the company suspects that it is automated spam, or that it has been compromised, usually by having its password hacked or leaked. Most spam accounts are quickly removed. But until now, even after Twitter privately identified an account as suspicious and locked it, that account would still be included among the legitimate followers of a user.

Most of the time, according to Twitter, the locked accounts are not included in the monthly active user count it reports to investors each quarter, a critical Wall Street metric for social media companies. But the locked accounts were nevertheless allowed to inflate the follower counts of a large swath of users.

That choice helped propel a large market in fake followers. Dozens of websites openly sell followers and engagement on Twitter, as well as on YouTube, Instagram and other platforms. The Times revealed that one company, Devumi, sold over 200 million Twitter followers, drawing on an estimated stock of at least 3.5 million automated accounts, each sold many times over.

Tens of thousands of automated accounts were created by stealing profile information from real users, including minors. One such victim, a teenager named Jessica Rychly, had her account information — including her profile photo, biographical information and location — copied and pasted onto a fake account that retweeted cryptocurrency advertisements and graphic pornography.

Twitter officials believe that the new policy will disrupt the marketplace for fake followers and curb abusive practices used to create fake accounts: Since suspicious accounts will now be stripped from users’ followers, the company hopes there will be less incentive to purchase fakes in the first place.

Twitter has also begun to permanently remove more suspicious accounts. After the Times’ investigation was published in January, Twitter removed over 1 million accounts from the followers of Devumi customers — accounts that the company said violated its spam policies.

The Washington Post reported last week that Twitter suspended more than 70 million accounts in May and June.

Twitter estimates that as a result of Thursday’s changes, the average user will see his or her follower number drop by four — but that number would be much higher for some accounts.

“As part of our renewed focus on public healthy conversation, and certainly some of the information that the New York Times was able to provide in their story, we felt it was an important step to take,” Harvey said.

© 2018 The New York Times Company