Providers of very large online platforms and of very large online search engines should also be diligent in the measures they take to test and, where necessary, adapt their algorithmic systems, not least their recommender systems. They may need to mitigate the negative effects of personalised recommendations and correct the criteria used in their recommendations. The advertising systems used by providers of very large online platforms and of very large online search engines can also be a catalyser for the systemic risks. Those providers should consider corrective measures, such as discontinuing advertising revenue for specific information, or other actions, such as improving the visibility of authoritative information sources, or more structurally adapting their advertising systems. Providers of very large online platforms and of very large online search engines may need to reinforce their internal processes or supervision of any of their activities, in particular as regards the detection of systemic risks, and conduct more frequent or targeted risk assessments related to new functionalities. In particular, where risks are shared across different online platforms or online search engines, they should cooperate with other service providers, including by initiating or joining existing codes of conduct or other self-regulatory measures. They should also consider awareness-raising actions, in particular where risks relate to disinformation campaigns.
