While they are intended to prevent a company 's ads showing up on undesirable websites they are often ignored by marketers and digital agencies in programmatic ad buying , particularly if they are incentivised solely on delivery efficiency and reach . Chris Horn , head of marketing science at Huge , said : " It 's a problem clients knowingly or unknowingly push their agencies into , and agencies do n't always have the time or resources to push back " .
While blacklists are intended to prevent a brand's ads showing up on undesirable sites they are often ignored by marketers and digital agencies in programmatic ad buying, particularly if they are incentivised solely on delivery efficiency and reach. Michael Horn, MD of data science at Huge, said: "It's a position clients knowingly or unknowingly push their agencies into, and agencies don't always have the time or will to push back".