Most vendors in our space have to implement frequency caps to limit overexposure to any given user. However, our engine has an incorporated user fatigue algorithm that prevents this from happening. It means we don’t need to add hard caps.
Since Criteo pays for all inventory on a CPM and sells on a CPC, this algorithm is mutually beneficial. If a user is unengaged and not clicking on banners/returning to the site, Criteo would lose money if we continued to serve impressions.