If you log in into your Google account, any activity on the web will be recorded. That include, what you search on the internet using Google search engine.
The data which Google track is, the keyword do you use, the website you visit based on your search term, and how many time you visit those sites.
Well this is sucks, but Google give us an option to turn off the search tracking facilities. I don’t know if they are still tracking us or not, but at least this feature can blocked someone from tracking you (as preventive action if your account has been compromised).