Through collecting your IP address, cookie information, and then tracking this down to your machine, Google can and does keep every search you complete on your machine. Yes, that is right, every search you do if required by law, Google Inc., would give up and reveal the exact person who made those searches.This is from an article at:
http://microdoc-news.info/home/NewsOnGoogle/2003/08/06.html/1which describes how Google tracks your clicks, and how you can stop it from doing this.
There is also a way you can maintain your privacy by changing some security settings in your browser pertaining to "cookies" (a permanent identifier which some websites store on your computer). Below is this method which you can follow to prevent sites like Google from putting a cookie on your machine and thereby maintaining a permanent record of all the links you've clicked on over time. (I did this in Mozilla - I guess something similar would work in Microsoft's Internet Explorer.)
(1) In my browser Mozilla, I went into
'Edit > Preferences'
(2) I then clicked on:
'Privacy & Security > Cookies'
(3) I left the radio-button 'Enable cookies based on privacy settings' checked, and clicked on the button 'View' to make sure my Privacy Level was set to 'Medium' and then hit OK.
(4) VERY IMPORTANT:
I checked the box 'Ask me before storing a cookie'.This slows things down a bit the next time you log into DU, because a dialog comes up saying "Do you want to allow this website to store a cookie on you?" But I hit "Yes" and there is also a checkbox on this dialog where you can say "Always accept cookies from this website" so you won't get asked anymore for a cookie when logging onto DU.
On other websites where you don't want them storing info on you (such as Google), when this dialog comes up you can say "No" and prevent Google from storing a permanent record on where you've clicked.