Investigation into 4chan and its compliance with duties to protect its users from illegal content

Ofcom has today opened an investigation into the online discussion board ‘4chan’. The investigation will consider 4chan’s compliance with its duties under the Online Safety Act 2023 ('the Act').

Section 9(2) of the Act requires all user-to-user and search services in scope of the Act to undertake an illegal content risk assessment by 16 March 2025. Amongst other things, this requires services to assess the risks of users encountering illegal content on their platforms, including priority illegal content (as defined by the Act).

Section 10 of the Act imposes duties on providers of regulated user-to-user services to take or use:

1. proportionate measures to effectively mitigate and manage:
   • the risk of the service being used for the commission or facilitation of a priority offence; and
   • the risks of harm to individuals identified in their illegal content risk assessment.
2. proportionate systems and processes to:
   • prevent individuals from encountering priority illegal content; and
   • minimise the length of time for which any priority illegal content is present and to swiftly take down illegal content once they become aware of it.

Services must also include provisions in the terms of service specifying how individuals are to be protected from illegal content, apply those terms consistently and ensure the terms of service are clear and easily accessible.

These ‘Illegal Content Duties’ came into effect on 17 March 2025.

Regulated user-to-user service providers can comply with the Illegal Content Duties by implementing measures recommended in Ofcom’s illegal content Codes of Practice for user-to-user services issued on 24 February 2025 (the ‘Codes of Practice’), or through alternative measures.

Ofcom has powers under section 102(8) of the Act to require persons to respond to an information notice in the manner and form specified.

Investigation

On 14 April 2025, Ofcom issued a formal information notice to the provider of the service 4chan requesting a copy of the record of its Illegal Content Risk Assessment, as part of our Risk Assessment Enforcement Programme. At the date of opening this investigation, no response has been received to the information notice. 

Ofcom’s investigation will examine whether there are reasonable grounds to believe that 4chan has failed, or is failing, to comply with its duty to respond accurately to an information notice sent under the Act, as well as its duty to complete and keep a record of its Illegal Content Risk Assessment. The investigation will also consider whether there are reasonable grounds to believe that 4chan has failed, or is failing, to comply with its duties to protect its users from illegal content under section 10.

Ofcom’s Online Safety Enforcement Guidance sets out how Ofcom will normally approach enforcement under the Act. This includes our approach to information gathering and analysis and the procedural steps we must take to fairly determine the outcome of the investigation.

Where we identify compliance failures, we can impose fines of up to £18 million or 10% of qualifying worldwide revenue (whichever is greater). In the most serious cases of non-compliance, and where appropriate, given the risks of harm to individuals in the UK, we can seek a court order to require third parties to take action to disrupt the business of the provider. This may require third parties (such as providers of payment or advertising services, or Internet Service Providers) to withdraw services from, or block access to, a regulated service in the UK.

We will provide an update on this investigation in due course.