Twitter has never stood up for the interests of Twitter users over Trump before. That has now changedTwitter finally got something right. After a torrid week of acrimony, bluster and a president unleashing a flurry of tweets threatening violence and terrifying harassment on a mid-level Twitter employee, Twitter took a stand on Thursday night that set the model for proper “content moderation” on its platform.After President Donald Trump called for violence against American citizens –something he has done multiple times before at his rallies and on Twitter – Twitter placed a cover over the dangerous tweet, making people read the warning before reading it. Once people read the tweet, they could not “like” it or reply to it, thus slowing its flow through the system and muffling some of the madness.Twitter ruled that the tweet “violated its rules about glorifying violence”. This is the first time that Twitter has chosen to enforce its own rules when it came to the company’s most famous and eighth-most-followed account (former President Barack Obama is first, much to Trump’s frustration).Trump was reacting to the third night of anti-violence and anti-racist protests in Minneapolis, Minnesota. George Floyd, an African American man, died on Monday after a white police officer restrained Floyd by placing a knee on his neck for eight minutes while the dying man gasped, “I can’t breathe.” Bystanders told police, “He is human” and “Check his pulse.” Four officers were fired and one is currently facing criminal charges for Floyd’s death. But the record of local prosecutors in the United States holding their own police officers accountable is poor.Protests also broke out in at least nine other American cities, reminding Americans that their law enforcement systems too often consider African Americans disposable and beneath concern for their basic safety and human rights.Trump, who has consistently sided with violent white supremacists and has overseen anti-immigration policies that would stem ethnic diversity in the United States, issued a stern threat to anti-racist protesters in the covered tweet. Once Twitter users encountered the cover, they could click “View” to read the message from the president: “… when the looting starts, the shooting starts. Thank you!”So Trump’s expression stands, adding to the evidence that the most powerful nation in history is run by an unhinged, petulant whiner who wants nothing more than to make people forget that more than 100,000 Americans have died this year because of Covid-19 and more than 40 million have lost jobs. Importantly, by letting the message stand, Twitter has started a conversation, not stopped it. Trump and his followers will whine about “censorship” but their concerns are unlikely to concern any but those deeply committed to Trump’s cause, which is overwhelmingly an attempt to disrupt any attempt to think clearly about the damage he has done. Twitter had several options in this case. It could have deleted the offending tweets, but that would have raised interest in them and risked making the conversation about deletion rather than about Trump’s calls for violence. Twitter could have removed Trump’s account entirely for repeatedly violating rules against inciting violence and spreading misinformation about public health and voting rights. And there are strong arguments for doing just that, not least of which is the fact that Trump uses Twitter to distract people from the crucial issues of the moment and his own mismanagement of crises. Twitter still has that option if Trump continues to use Twitter to endanger innocent people – which he surely will.If Trump could not tweet, we might all be better able to focus. His eruptions would have to occur live, in front of reporters and viewers, so they could be contextualized and mitigated. But that’s not in the immediate interest of Twitter. The blowback against Twitter and its innocent employees would be fierce and probably violent.Earlier in the week Twitter affixed a useless “fact check” tag to two of Trump’s tweets about postal voting. > Trump essentially commanded his militia of supporters to flood the employee with death threats. That’s exactly what happenedThis sent Trump into a rage. It spurred him to issue a silly “executive order” that demonstrated that no one in the White House seems to understand the very Twitter-shielding law Trump was criticising or the fact that the executive branch of government has no say over that law. While the “executive order” was harmless and comical, Trump also unleashed a barrage of terror on to an innocent employee of Twitter. After the New York Post and then Fox News revealed that this employee had participated in the decision to affix the “fact check” label to the tweets, Trump named him in a tweet. By doing so Trump essentially commanded his militia of supporters to flood the employee with death threats. That’s exactly what happened. This sort of behavior has been a constant tactic of authoritarian nationalists like Prime Minister Narendra Modi of India. Modi’s political supporters are known to flood journalists and critics of the government with life-upending threats and even actual violence and murder. Modi uses Twitter, Facebook and WhatApp to execute his campaigns of terror. Trump has learned well from Modi. Despite all the pain they sparked for the Twitter employee, the “fact checks” did nothing to help anyone. No one is likely to click on the tiny link to read further information about postal voting. The fact that Trump reacted became the much bigger story, thus defeating the purpose of the “fact check”. It taught no one anything and did not impede the spread of misinformation. The later move, however, is much more effective and appropriate. The standard for such content moderation should be the potential for harm rather than the truth or falsity of the claims. Determining the “truth” of a tweet is folly. Judging “truth” itself is hardly something the staff at Twitter should or could do. “Truth” is not the real issue or the problem.Right now Twitter, Facebook and YouTube are leveraged to flood our collective consciousness with stimuli. The specific nature of the stimuli matters less than the overall experience of them. We are living in a cacophony of crap. When someone powerful wishes harm on others, the standard is easier to judge and much more urgent. Hours after Twitter covered Trump’s tweet, the official White House account quoted the tweet in its entirety, escaping Twitter’s efforts. Twitter has done nothing to change how it presents the thousands of earlier dangerous tweets from Trump. And everything Trump tweets ends up on Facebook, which has seven times the number of American users that Twitter does. So this all could be futile anyway.There is no way Twitter can scale up this policy to cover every violent world leader, let alone the 330 million Twitter accounts around the world. So we should not expect this practice to “fix” Twitter and make it a more useful and less destructive force in the world. People will still get hurt because Twitter remains fundamentally ungovernable. But slowing down Trump’s calls for violence is the right move for Twitter. It just happens to be the right move for the rest of us as well.Companies should do what is best for themselves, their workers, customers, users and shareholders. There is no reason to expect companies to care about anything so vague and contradictory as the “public interest”. They have no incentive to do so. But a company like Twitter has a long-term interest in making the experience of Twitter as pleasant and untroubling as possible for users and advertisers. That’s why content moderation matters.Twitter has never stood up for the interests of Twitter users over Trump before. It has bent to Trump’s will time and time again. This move demonstrates that Twitter has learned a few things, albeit at least three years too late. * Siva Vaidhyanathan is a regular columnist for the Guardian, a professor of media studies at the University of Virginia, and the author of Antisocial Media: How Facebook Disconnects Us and Undermines Democracy.