Google uses a unique cookie for each browser used by an individual user on a computer. This cookie contains information that allows Google to identify records about that user on its database. This cookie is submitted every time a user launches a Google search, visits a site using AdSense etc. The information stored in Google's database, identified by the cookie, includes

Everything you search for using Google

Every web page you visit that has Google Adsense ads

How would you prevent Google from storing your search keywords?