When you search on DuckDuckGo, we can show you an ad based on the keywords you type in. That’s it. And it works.

Almost all of the money search engines make (including Google) is based on the keywords you type in, without knowing anything about you, including your search history or the seemingly endless amounts of additional data points they have collected about registered and non-registered users alike. In fact, search advertisers buy search ads by bidding on keywords, not people. It makes intuitive sense, too. If you search for ‘car’, you are more likely to respond to a car ad than something you searched for last week.