In the context of contextual advertising, what replaces user profiles for ad targeting?

In the context of contextual advertising, the immediate context of the user's search query and the content of the webpage replace user profiles for ad targeting. Contextual advertising focuses on the relevance of the ad to the specific search terms used by the user or the topic being discussed on the webpage they are currently viewing, rather than relying on historical data about the user's browsing behavior or demographics. For example, if a user searches for 'gardening tips', ads for gardening tools or plant nurseries would be shown based on the search query itself, without needing to know anything else about the user.