(NewsNation) — Hundreds of employees signaled they are leaving Twitter after an ultimatum by new owner Elon Musk, leaving many to wonder about the future of the social media platform.

Earlier this week, Musk sent an email to staff at Twitter, saying it is a software and servers company at its heart, and he plans to build a “breakthrough Twitter 2.0.”

Musk gave workers a Thursday deadline to commit to working in an “extremely hardcore fashion” or resign with three months’ severance pay.

After his announcement, staffers started posting a “salute” emoji on the company’s internal Slack messaging board, though a current employee told the Associated Press it might have been out of solidarity with departing colleagues.

Others posted about their resignations from Twitter on the platform itself, including Jess DeBolt Bermon, who works on the site’s Entertainment Partnerships.

“Deciding to join @Twitter 7.5 years ago was one of the easiest decisions ever made. Deciding to leave today was 100% the opposite,” Berman wrote Thursday afternoon. “I will miss the people, the fun, the love, warmth and kindness within and surrounding this company. Thank you, Tweeps.”

Another Twitter user, Bionca, wrote that she was resigning after five “incredible years.”

“What a ride!” she said. “Twitter was my dream job and I’m so fortunate to have lived it. Until next time.”

Musk completed the $44 billion Twitter takeover in late October. He fired half its full-time workforce in November, and on his first day, fired top executives. The Associated Press reports that a number of engineers also came out and said they were fired this week after saying something critical of Musk.

With all of the chaos now surrounding the company, many took to social media to joke or lament the possibility of Twitter “shutting down.”

On Friday morning, #RIPTwitter, #Twittershutdown and #Elon were trending on the site in the United States.

Even Musk made a few jokes about it.

“How do you make a small fortune in social media?” he asked in a tweet with over 300,000 likes. “Start out with a large one.”

It is still not clear how many of Twitter’s staff took Musk up on his severance offer. But the new round of departures comes as Twitter gears up for the 2022 FIFA World Cup — one of its busiest events.

For now, though, Twitter is still online, and plans to relaunch its system where people can get a blue check if they pay $8 for Twitter Blue on Nov. 29.

Twitter did not respond to a message from the AP seeking comment.

The Associated Press contributed to this report.