Twitter’s former CEO Jack Dorsey openly criticized Elon Musk’s leadership of the company in a series of social media posts Friday, writing that “it all went south” and Musk “should have walked away” from the acquisition.

Users of Bluesky, a buzzy new social media platform that is being touted as a potential alternative to Twitter, prompted the discussion. They asked Dorsey if he believed Musk was the right leader for Twitter, to which Dorsey replied, “No.”

“No. Nor do I think he acted right after realizing his timing was bad. Nor do I think the board should have forced the sale. It all went south,” Dorsey wrote. He added that he is glad new social media platforms like Bluesky are being built. Dorsey has backed Bluesky since 2019, when he was still serving as Twitter’s CEO.

Dorsey previously called Musk the “singular solution” to take over Twitter. In a tweet from April 2022, Dorsey said he trusted Musk’s “mission to extend the light of consciousness” through the platform.

But a year later, Dorsey’s opinion appears to have soured.

Musk, who is also the CEO of Tesla and SpaceX, has drawn ire for his tumultuous takeover of Twitter, which he acquired for $44 billion late last year. Musk’s steep job cuts, sweeping policy and feature changes have shaken the confidence of advertisers, politicians and celebrities, among others.

Many have publicly announced their decision to leave or reduce their use of the platform, including Elton John, Jim Carrey and MTA, New York City’s public transit agency.

Soon after making a best-and-final bid to purchase Twitter for $44 billion, or about $54.20 per share, Musk tried to back out of the deal he made to buy the company.

He would have had to pay a $1 billion penalty, otherwise known as a “breakup fee,” to do so and prove to a Delaware court that he had a good reason for walking away. While Musk did take the matter to court, he ended up going through with the deal anyway.

Dorsey, who is still a Twitter shareholder, championed the deal at the time. But on Friday, he wrote that things should have gone differently. “I think he should have walked away and paid the $1b.” It is not clear that Musk, or Twitter, even had that option.

A decade ago, Twitter’s future was looking bright. The company was benefiting from a flood of funding into the social-networking space, eventually leading to an IPO in 2013 that raised $1.8 billion.

Now the company is back in private hands. And they happen to be the hands of Elon Musk, the richest person in the world and one of the app’s most high-profile provocateurs.

It’s a massive moment. Twitter has become a key place for people to debate, joke and pontificate in their own circles of politics, sports, tech and finance. It’s also served as a platform that gives voice to the voiceless, helping protesters organize and express themselves in repressed regimes around the world.

In recent years, however, Twitter and social media rivals like Facebook have been at the center of controversy over the distribution of fake news and misinformation, sometimes leading to bullying and violence.

Investors had grown concerned about Twitter as a business. The company was generally unprofitable, struggled to keep pace with Google and Facebook, and often killed popular products with no real explanation.

What follows is a brief history of Twitter, which — despite its many flaws — is one of the most iconic companies to come out of Silicon Valley in the past 20 years.

2006

In March, Jack Dorsey, Noah Glass, Biz Stone, and Evan Williams created Twitter, which was originally a side project stemming from the podcasting tool Odeo. That month, Dorsey would send the first Tweet that read, “just setting up my twttr.”

2007

In July, Twitter received a $100,000 Series A funding round led by Union Square Ventures. The app’s popularity started to explode after being heavily promoted by the tech community during the annual South by Southwest conference.

2008

Dorsey stepped down as CEO in October, and was replaced by Williams. According to the book “Hatching Twitter” by journalist Nick Bilton, Twitter’s board fired Dorsey over concerns about the executive’s management style and public boastings.

2009

Twitter’s popularity continued to soar, leading to a high-profile appearance from Williams on Oprah Winfrey’s talk show alongside celebrity Ashton Kutcher. Kutcher would also write about Williams and Stone as part of Time Magazine’s Time 100 issue. Twitter was now a mainstream phenomenon.

2010

Twitter reached space, with NASA Astronaut Timothy Creamer sending the first tweet live from outer orbit. Behind the scenes, however, management woes continued with Williams stepping down as CEO, replaced by operating chief Dick Costolo.

2011

Twitter became an essential social media tool used during the Arab Spring, the wave of antigovernmental protests throughout Egypt, Libya and Tunisia. Protesters used the site to post reports and to organize. As the Pew Research Center noted, Twitter’s role in “disseminating breaking news” was not “not limited to the Arab uprisings – the death of Whitney Houston, for example, was announced on Twitter 55 minutes prior to the AP confirming the story.”

2012

Twitter’s reach expanded to 200 million active users. Barack Obama used the “platform to first declare victory publicly in the 2012 U.S. presidential election, with a Tweet that was viewed approximately 25 million times on our platform and widely distributed offline in print and broadcast media,” according to corporate filings.

2013

Twitter went public in November. The combined wealth of Williams, Dorsey, and Costolo hit roughly $4 billion.

“I think we’ve got a tremendous set of thoughts and strategies to increase the slope of the growth curve,” Costolo told CNBC at the time. “I would consider some of them tactics, some of them broader strategies, in service of doing what I referred to as bridge the gap between the massive awareness of Twitter and deep engagement of the platform.”

2014

Slowing user growth led to several stock drops and analyst downgrades. Twitter also deemed 2014 the year of the “selfie.”

2015

Compared to rivals like Google, Facebook, and even LinkedIn, Twitter was starting to look like the runt of the Internet litter. Twitter was still unprofitable as its ad business struggled mightily against its larger competitors. Dorsey would also return as CEO of the company, while still maintaining the top job at his other company, Square (now Block).

2016

Rumors began circulating that Twitter was looking to be acquired, with Salesforce as a potential suitor. Meanwhile, Twitter and Facebook were criticized for their role in letting prominent users like Donald Trump, who would win the U.S. presidential election that year, spread misleading information without consequence.

“Having the president-elect on our service using it as a direct line of communication allows everyone to see what is on his mind in the moment,” Dorsey said at the time. “We’re definitely entering a new world where everything is on the surface and we can all see that in real time and we can have conversations about it.”

2017

For a moment, Twitter appeared to be on the upswing. Its stock was finally trending upward as the company’s finances were improving. Meanwhile, Trump as president continued to use Twitter as his megaphone. According to Twitter’s own data, “Trump was the most-tweeted-about global leader in the world and in the United States” that year, CNBC reported.

2018

Dorsey and Facebook’s then-operating chief Sheryl Sandberg testified before the Senate Intelligence Committee about alleged interference by Russia-linked actors in the 2016 election. Trump and fellow Republicans became increasingly vocal about alleged political bias by Twitter and other social media sites.

“In fact, from a simple business perspective and to serve the public conversation, Twitter is incentivized to keep all voices on the platform,” Dorsey said at the time.

2019

Analysts found correlations between President Trump’s voracious use of Twitter and various markets, including gold, underscoring the cultural power of Twitter. Trump met with Dorsey — a Twitter spokesperson said “Jack had a constructive meeting with the President of the United States today at the president’s invitation.”

“They discussed Twitter’s commitment to protecting the health of the public conversation ahead of the 2020 U.S. elections and efforts underway to respond to the opioid crisis,” the spokesperson said.

2020

As Covid-19 spread across the globe, the spread of misinformation dominated the online conversation. And Twitter continued to struggle to grow its business. The service was also hacked that year, and miscreants gained access to over a dozen high-profile accounts, including those controlled by Joe Biden, Jeff Bezos, and Musk

2021

Twitter permanently banned Trump over inflammatory comments the president made during the U.S. Capitol riots in January that the company said could lead to “further incitement of violence.” Trump would allege that Twitter workers “coordinated with the Democrats and the Radical Left in removing my account from their platform, to silence me.” Later, Dorsey suddenly stepped down as CEO and was replaced by Parag Agrawal, the company’s chief technology officer.

2022

Musk took over Twitter after a protracted legal spat that would have culminated this week in a trial in Delaware’s Court of Chancery. The Tesla CEO agreed in April to pay $44 billion for Twitter, but then attempted to renege on the deal. He changed course and opted to proceed, walking into the company’s San Francisco office on Wednesday with what appeared to be a porcelain bathroom sink in his hands.

“Entering Twitter HQ – let that sink in!” he tweeted, with a video of his entrance.

Musk immediately began making changes, firing Agrawal, finance head Ned Segal, and head of legal policy Vijaya Gadde.

WATCH: Billionaire Elon Musk steps into Twitter HQ, sink in hand