In a major regulatory move, the European Union has announced a formal investigation into X, the social media platform owned by Elon Musk. The investigation accuses X of failing to counter illicit content and disinformation, lacking transparency about advertising practices, and engaging in “deceptive” design practices. This inquiry is the most substantial regulatory action taken against X since Mr. Musk acquired the platform, previously known as Twitter, last year.

One of the main concerns raised by researchers is that X's new content moderation policies have led to an increase in incendiary content on the platform. This rise in inflammatory material has caused brands to scale back their advertising, raising further concerns about the impact of X's practices. The European Union is utilizing the authority granted by the Digital Services Act, which was passed last year, to investigate X. This law empowers regulators to compel social media companies to police their platforms for hate speech, misinformation, and other divisive content.

The investigation into X marks the first time the European Union is employing its new powers under the Digital Services Act. This act covers other major platforms such as Facebook, Instagram, Snapchat, TikTok, and YouTube. The European Commission, the executive branch of the 27-nation bloc, had previously indicated its intention to scrutinize X's business practices. In October, regulators initiated a preliminary inquiry into the spread of "terrorist and violent content and hate speech" on X during the Israel-Gaza conflict.

Margrethe Vestager, the European Commission's executive vice president overseeing digital policy, stated that the evidence gathered thus far is sufficient to open a formal proceeding against X. The Commission aims to thoroughly investigate X's compliance with the Digital Services Act to protect European citizens online. X has responded by affirming its commitment to complying with the act and cooperating with the regulatory process. The company emphasizes its dedication to creating a safe and inclusive environment for all users while safeguarding freedom of expression.

This investigation highlights a significant disparity between the United States and Europe in terms of regulating the internet. While the United States largely allows online posts to go unregulated due to free speech protections, European governments, driven by historical and cultural reasons, have imposed more restrictions on hate speech, incitement to violence, and harmful material. The Digital Services Act aims to compel companies to establish consistent procedures for complying with content rules online.

The investigation launched on Monday is the beginning of a process with no specified deadline. It is expected to involve interviews with external groups and requests for additional evidence from X. If found guilty of violating the Digital Services Act, X could face fines of up to 6 percent of its global revenue.

Since Mr. Musk took control of X, the platform has undergone significant changes. He dissolved the trust and safety council, revamped content moderation practices, and welcomed numerous previously banned users back to the platform. However, various studies have reported a sharp increase in antisemitic content and hateful posts since the ownership change. The Institute for Strategic Dialogue found that antisemitic posts in English more than doubled on X following Mr. Musk's takeover. The European Commission also discovered a 36 percent increase in engagement with pro-Kremlin accounts after Mr. Musk lifted mitigation measures.

As natural disasters occurred worldwide this summer, X became a hotspot for spreading climate misinformation. The platform received a low score of one out of 21 for its efforts in combating climate-related falsehoods. Officials have raised concerns about X's content moderation policies in languages other than English, especially with upcoming elections across Europe in 2024. The investigation will also scrutinize X's measures to address the spread of false information. X relies on a feature called Community Notes, allowing users to add context to potentially misleading posts. However, EU officials question whether this approach is sufficient. Regulators will also examine how posts by X users who pay for authentication, indicated by a blue check mark, receive more visibility.

This investigation will test the European Union's ability to enforce change in the behavior of large internet platforms. Musk, a staunch advocate for free speech rights, withdrew X from the EU's voluntary code of practice against disinformation in May. He challenged regulators to provide evidence of illicit content on X and urged them to make the violations public. The outcome of this investigation remains uncertain, and updates will be provided as the story develops.