Google Adsense no offers Ads that are based on your search history too. Formerly the ads were more focused on context. You could define areas for the bot to look for keywords in your webpage. For example on this site you would see more ads related to Computers Software etc. Not anymore though. Google has started showing ads in a different way now.
Instead of contextual ads, Google will now show ads based on your Google search history and Youtube history. Here is a screenshot of the ads shown to me on this site.
The page is about how to save protected images from Flickr, but the ads are all about electronics. That is because I had viewed a lot of videos on Youtube related to electronics and done some searches too.