Google AdSense works by displaying ads relevant to a page. To get relevant ads, Google AdSense crawler crawls your site and extract keywords from the pages it visit. When a visitor visits a page on your site, Google will serve ads based on the extracted keywords that Google AdWords advertisers bid on.
With that in mind, it’s important for Google AdSense crawler to get the right keyword from your page, as if it doesn’t, it will either display irrelevant ads or worst, PSAs or Public Service Avertisements. Irrelevant ads gets less click from your site’s visitors, and PSAs don’t pay at all.
Keyword targeting for Google AdSense in a sense is similar to keyword targeting in SEO or Search Engine optimization, with some unique targeting features of its own.
Google AdSense by default serve ads based on your visitor’s browsing history that Google stores in browser’s cookie. Depending on your website’s niche, disabling it can serve more targeted ads to your visitors and increase your AdSense earnings.
A niche with high competition in Google AdWords (where there are a lot advertisers bid for keywords in your site) would benefit from disabling the option, while site’s with less targeted keyword might suffer.
To disable 'Interest-based ads, go to Allow & block ads → Advanced settings from your Gooogle AdSense dashboard.
From there, disable the interest-based ads in the Interest-based Ads Preferences section.
