With Personalized ads (formerly known as interest-based advertising), Google AdSense by default serve ads based on your visitor's browsing history that Google tracks via its various tracking methods. Depending on your website's niche, disabling it can serve more relevant 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.

Follow these steps to disable Personalized ads for your Adsense account;

1. Log in to your Adsense account.
2. From the sidebar, click on Allow & block ads.
3. Go to All my sites.
4. Click on the Ad serving tab.
5. Toggle User-based ads off from the Personalized ads section.