Elon Musk’s Twitter Teeters on the Edge After Another 1,200 Leave

Elon Musk sent a flurry of emails to Twitter employees on Friday morning with a plea.

“Anyone who actually writes software, please report to the 10th floor at 2 p.m. today,” he wrote in a two-paragraph message, which was viewed by The New York Times. “Thanks, Elon.”

About 30 minutes later, Mr. Musk sent another email saying he wanted to learn about Twitter’s “tech stack,” a term used to describe a company’s software and related systems. Then in another email, he asked some people to fly to Twitter’s headquarters in San Francisco to meet in person.

Twitter is teetering on the edge as Mr. Musk remakes the company after buying it for $44 billion last month. The billionaire has pushed relentlessly to put his imprint on the social media service, slashing 50 percent of its work force, firing dissenters, pursuing new subscription products and delivering a harsh message that the company needs to shape up or it will face bankruptcy.

Now the question is whether Mr. Musk, 51, has gone too far. On Thursday, hundreds of Twitter employees resigned after Mr. Musk gave them a deadline to decide whether to leave or stay. So many workers chose to depart that Twitter users began questioning whether the site would survive, tweeting farewell messages to the service and turning hashtags like #TwitterMigration and #TwitterTakeover into trending topics.

Some internal estimates showed that at least 1,200 full-time employees resigned on Thursday, three people close to the company said. Twitter had 7,500 full-time employees at the end of October, which dropped to about 3,700 after mass layoffs this month.

The employee numbers are likely to remain fluid as the dust settles on the exits, with confusion abounding over who is keeping a tally of workers and running other workplace systems. Some employees who quit said they were separating themselves from the company by disconnecting from email and logging out of the internal messaging system Slack because human resources representatives were not available.

Mr. Musk and representatives for Twitter did not respond to requests for comment.

But the billionaire tweeted on Friday what he said would be changes to Twitter’s content policy. Hateful tweets will no longer be promoted algorithmically in users’ feeds, he said, but they will not be taken down. He also reinstated several previously banned accounts, including those of the comedian Kathy Griffin and the author Jordan Peterson, and posted a poll asking users to vote on whether Twitter should reinstate former President Donald J. Trump’s account.

Perhaps the most crucial question now is how Twitter can keep running after the giant reduction to its work force in such a short time. The effects of the cuts and resignations have played out across the company’s technology teams, people with knowledge of the matter said.

One team known as Twitter Command Center, a 20-person organization crucial to preventing outages and technology failures during high-traffic events, had multiple people from around the world resign, two former employees said. The “core services” team, which handles computing architecture, was cut to four people from more than 100. Other teams that deal with how media appears in tweets or how profiles show follower counts were down to zero people.

“Wednesday offered a clean exit and 80 percent of the remaining were gone,” Peter Clowes, a senior software engineer, tweeted on Thursday about the departures on his team. “3/75 engineers stayed.” He said on Twitter that he quit on Thursday.

Mr. Musk is also considering shuttering one of Twitter’s three main U.S. data centers, a location known as SMF1 in Sacramento, which is used to store information needed to run the social media site, four people with knowledge of the effort said. If the data center in Sacramento is taken offline, it will leave the company with data centers in Atlanta and Portland, Ore., with potentially less backup computing capacity in case something fails.

Twitter is still operating, but it may become harder for the company to fix serious issues when they come up, former employees said. One former Twitter engineer likened the service’s current state to Wile E. Coyote, the Looney Tunes cartoon character, as he runs off the edge of a cliff. Though he may still be running in midair for some time, once he looks down, he drops like a stone.

“The larger and more prominent a platform is, the more care and feeding is needed to keep it running and maintain the expectations of the users,” said Richard Forno, the assistant director of the Center for Cybersecurity at the University of Maryland, Baltimore County. “It’s a huge challenge.”

The employee reductions are coinciding with Twitter’s entering one of its busiest periods in terms of visitors to the site. The World Cup, which begins on Sunday, is expected to bring a deluge of traffic to Twitter, which is the world’s fourth most visited website, according to Similarweb, a digital intelligence platform that tracks web traffic. Twitter gets 6.9 billion visits each month, slightly more than Instagram’s 6.4 billion, though far fewer than Google, YouTube or Facebook, according to Similarweb estimates.

On Twitter late Thursday, Mr. Musk professed confidence that the service would be fine.

“The best people are staying, so I’m not super worried,” he tweeted.

Fortune reported earlier that 1,000 to 1,200 Twitter employees had resigned. The Information earlier reported on some of Twitter’s infrastructure issues. The Verge earlier reported on departures from the Twitter Command Center.

Keeping a site like Twitter online is typically a task for senior engineers, who must constantly guard against cyberattacks and monitor web traffic to ensure servers are not overloaded, Dr. Forno said. If too many veteran employees depart, leaving Twitter without the expertise or manpower to monitor or quickly fix issues, problems could start, he said.

Many tech issues can be fixed remotely, but some may require workers at Twitter’s data centers around the country, Dr. Forno added. If issues fall through the cracks, Twitter users are not likely to see the site disappear all at once, at least at first. But timelines could start refreshing more slowly, the site might struggle to load and users would find Twitter to be full of glitches.

“It’s like putting a car on the road, hitting the accelerator and then the driver jumps out,” he said. “How far is it going to go before it crashes?”

Inside Twitter on Friday, remaining employees said they were bewildered by Mr. Musk’s changing directives. The company had said on Thursday afternoon that it was closing “our office buildings” and disabling employee badge access until Monday. But in his emails on Friday, Mr. Musk appeared to want to talk to people in person at the company’s San Francisco offices.

Employees were also having difficulties figuring out who was still on staff, and what areas of infrastructure needed more support to keep things up and running.

One worker who wanted to resign said she had spent two days looking for her manager, whose identity she no longer knew because so many people had quit in the days beforehand. After finally finding her direct supervisor, she tendered her resignation. The next day, her supervisor also quit.

Others were spending hours trying to track down which teams they were on. Some said they were asked to oversee duties they had never handled before.

The changes were occurring in a near total information vacuum internally, employees said. Twitter’s internal communications staff has been laid off or left, and workers said they were looking outward for information from media articles. Mr. Musk has increasingly downplayed the role of traditional media over the past few months, citing Twitter as one of the best platforms for the rise in “citizen journalism,” as he put it.

Kate Conger contributed reporting.