The investigation will look into whether X did enough to curb the spread of illegal content and if measures to combat “information manipulation” were effective.
The Digital Services Act, which came into force in November 2022, requires very large online platforms and search engines to do more to tackle illegal content and risks to public security.
“Today's opening of formal proceedings against X makes it clear that, with the DSA, the time of big online platforms behaving like they are 'too big to care' has come to an end,” said the bloc's digital enforcer Thierry Breton.
“We will now start an in-depth investigation of X's compliance with the DSA obligations concerning countering the dissemination and amplification of illegal content and disinformation in the EU, transparency of the platforms and design of the user interface.”
The European Commission said a preliminary information-gathering investigation, launched in October, looked at “the dissemination of illegal content in the context of Hamas's terrorist attacks against Israel”.
The formal probe will examine four areas:
- Dissemination of illegal content
- Effectiveness of X's efforts to combat disinformation
- Suspected restrictions on giving researchers access to its data
- Suspected deceptive practices, known as dark patterns, related to its Blue Tick subscription product
After the October 7 attack, Mr Breton contacted X, Meta, TikTok and Alphabet reminding them of their DSA obligations to tackle harmful and illegal content.
The platforms responded by highlighting steps taken to stop disinformation on their platforms. Only X has so far received a formal request for information.
X remains committed to complying with the DSA and is co-operating with the regulatory process, the company said. “It is important that this process remains free of political influence and follows the law,” it added.
The EC will now carry out an in-depth investigation and send additional requests for information, conduct interviews and inspections.
It will also review measures taken by X to increase transparency and look at a suspected deceptive design of the user interface such as checkmarks linked to subscription products, the so-called Blue checks, it said.
The probe will focus on countering the dissemination of illegal content in the EU, and the effectiveness of measures taken to combat information manipulation, including the “community notes” system, the Commission said.
Earlier this year, X launched its community notes feature, which allows users to comment on posts to flag false or misleading content, in effect crowdsourcing fact checking to users rather than a dedicated team of fact checkers.