With days left for US President-elect Donald Trump to be sworn into office on January 20, the incoming administration’s future policies are being discussed on a range of issues with some clues from his last stint. One key sector is technology and how the new US president may regulate it. The question of online content moderation has increasingly been raised in US politics in recent years. Soon after a mob of Trump’s supporters stormed the US Capitol in 2021, his social media accounts were suspended by Big Tech companies like Twitter (now X) and Facebook for his alleged role in inciting violence and spreading misinformation. The incident spurred a renewed debate about Section 230 of the US Communications Decency Act — a controversial law that permitted the companies to ban Trump in the first place. In 2020, even before the Capitol riots, Trump repeatedly called for its repeal. Outgoing US President Joe Biden, too, has criticised the law. But another set of people believe it is essential for ensuring a relatively free, safe and open internet. We explain the debate. What is Section 230? Section 230 of the Communications Decency Act was passed in 1996 and provides legal immunity to internet companies for content shared on their websites. The Act was first introduced to regulate pornography online. Section 230 is an amendment that holds users responsible for their comments and posts online. According to the regulation, “No provider or user of an interactive computer service shall be treated as the publisher or speaker of any information provided by another information content provider.” This means that online companies, including social media platforms, are not liable for the content shared on their website by their users. So if a user posts something illegal on the website, the company is protected from lawsuits. The regulation also states that private companies can remove content that violates their guidelines and values. Thus, the companies were well within their rights when they suspended Trump’s accounts. The legislation was drafted over two decades ago to encourage up-and-coming technology companies and protect free speech, a principle enshrined in the First Amendment of the US Constitution. The international digital rights group Electronic Frontier Foundation calls Section 230 “the important law protecting internet speech”. What has it got to do with Trump? Four years later, what should and shouldn't be allowed on social media remains a contentious issue. Facebook founder Mark Zuckerberg, for instance, announced Meta’s decision to remove fact-checking labels on its platforms this month, replacing them with Community Notes to eliminate the possibility of professional fact-checkers having "biases". Many saw the move as more aligned with the incoming Trump administration, given his leader's earlier accusations of tech companies being biased against conservative voices. Following the unprecedented attack on the US Capitol, the finger of blame was pointed at social media platforms and online forums — where right-wing extremists were openly planning the attack for weeks. Facing growing backlash, companies started to crack down on users sharing inflammatory content online. From Google suspending pro-Trump social media site Parler to Trump being banned from nearly every major social media platform, Big Tech firms left no stone unturned. What enabled the swift and far-reaching response was Section 230. Why is Section 230 criticised? While the regulation has far-reaching consequences for social media platforms, its critics are quick to point out that it was passed before social media existed in its present, more advanced form. Political leaders and internet activists have long called for the law to be updated. Conservative critics of the regulation argue that it effectively permits Big Tech to participate in politically partisan activity. Republican lawmakers have alleged that platforms like Facebook exhibit a clear bias against conservatives and often abuse Section 230 to censor right-leaning users. On the other hand, some more liberal groups argue that the law permits websites like 4chan and Parler — used by many right-wing extremists — to refrain from moderating hate speech and violent content, regardless of how derogatory it may be. Has Trump earlier tried to change the law? In May 2020, then-President Trump issued an executive order that targeted the legal protection offered to tech companies under Section 230. He took this step after Twitter started labelling his tweets about voting by mail as misinformation. In response, the President alleged that the social media platforms were selectively censoring content as part of a wider conspiracy to “rig the election” against him. Trump’s order called for regulators to reassess the definition of Section 230 and directed agencies to collect complaints of political bias on social media platforms that could help revoke their legal immunity. This explainer contains portions of an earlier explainer first published in 2021.