How companies buy digital ads
The majority of ads don’t target specific websites. Instead, companies like us buy ad space from big ad networks (like Google) who use smart algorithms to choose who the ads are shown to based on different criteria. These networks create lists of people to show ads to based on their interests (like “green energy enthusiasts”).
That means our ads mostly get shown to people who have been on our website. Other times, the ad network’s algorithms might show ads to people who have an affinity for a particular subject, or person, related to what we do.
Say, for example, Google learned that Sir David Attenborough’s twitter followers were all green energy enthusiasts. They might suggest that we show ads to people who are interested in Sir David. It’s little like when you're shopping online and you get the section that says people who bought this also bought this – ‘people who like Sir David also like green energy’.
That means if an ad network has seen you on a site about Sir David, you’ll be shown related ads on all manner of websites you visit.
This is the case if you’re just looking at a local newspaper, a hobby site, or even if you’re going all over the internet looking at hate sites.
Ad platforms like Google’s will choose which ads to show on any given pageview, which means we are not selecting where our ads appear. However, Google, and others, usually have special filters so businesses can stop their ads appearing on sites with violent or sexual content – but nothing to filter hate speech specifically – so we take a proactive approach wherever we can to block particular sites.
What we do to prevent our ads appearing on offensive sites