For years, social media companies have largely shied away from taking comprehensive, drastic measures against misinformation, choosing to add labels and wade through a tough balance between appeasing both their conservative and liberal critics for doing too little or too much to monitor content shared on their platforms.

For many years, social media companies bristled at their characterization as media platforms and distributors of information for millions of people and downplayed their failure to effectively take responsibility to fact-check and label misleading information in real time.

Until last week. Following the pro-Trump rally and violent attack on the U.S. Capitol building in which five people died, social media companies like Twitter, Inc. (TWTR) and Facebook, Inc. (FB) have taken the strictest measures yet against disinformation.

On Friday, Twitter permanently suspended U.S. President Donald Trump's account "due to the risk of further incitement of violence" and several other accounts of his supporters, the company said in a statement. Trump was a prominent, prolific user of the platform and relied on his personal handle @realdonaldtrump instead of the official @POTUS account for years to reach his 88 million followers there.

Then Twitter introduced a tougher security policy on Monday, noting that it also purged at least 70,000 accounts affiliated with QAnon since Friday, according to Twitter's statement on Monday. "During the past several weeks, misleading and false information surrounding the 2020 U.S. presidential election has been the basis for incitement to violence around the country," the company said in a blog post on Monday. "Now that the results of the election have been officially certified by Congress, we updated our civic integrity policy on Friday to aggressively increase our enforcement action on these claims."

Seeing how its platform has enabled violent protests on the streets of Washington D.C. and in other cities has accelerated a lot of changes at Facebook too. Facebook said on Thursday that it would suspend Trump's accounts last week on both Facebook and Instagram for at "least the two weeks until the peaceful transition of power is complete." The social media giant also removed content that mentions "stop the steal" rallying cry of the Trump supporters, which is based on false allegations of a rigged presidential election. Snap Inc.'s (SNAP) Snapchat has also locked Trump's account.

It remains to be seen what the public admonishing of the Trump accounts will mean for Facebook, Twitter and social media landscape as a whole. Twitter's shares slumped 6.4%, while Facebook's stock fell 4% on Monday.

The big tech companies have quickly turned on Parler, an incumbent social media platform that has emerged as a safe haven for conservative voices and conspiracy theorists. Over the weekend, Apple, Inc. (AAPL), Amazon.com, Inc. (AMZN), and Alphabet Inc.'s (GOOGL) Google removed Parler from their app stores and web servers. By Monday, Parler was offline and suing Amazon for terminating Parler's account for political reasons "designed to reduce competition in the microblogging services market to the benefit of Twitter," according to the court filing.

There are many remaining questions about the likely future of Parler's and Twitter's current conservative base, where they land, and whether the outgoing U.S. president will find a new outlet or launch his own social media platform.

But we know that the political events of the first week of 2021 have forced social media companies to act and issue their harshest measures yet to fight disinformation in anticipation of further acts of violence. And by the time Biden is sworn in, the social media landscape, big tech's response to right-wing extremism, and the political appetite for regulating social media may look quite different.