Note there are now lots of "tracking" cookies that track which web sites you visit, what prooducts you are looking for and so on.
This information is sent back to central servers so adverts on web sites can be targetted at you.
If you run some anti virus or anti malware products they will often list all the tracking cookies they find.
When I do it on my family computer it is not unusuall to find around 500 tracking cookies.
Some anti virus and malware products allow you to delete these tracking cookies after they have found them.
Trouble is, as soon as you start visiting web sites again they start coming back.
The free product WinPatrol does allow you to create a list of cookies that you dont want (by name) and it will delete them if a web site tries to create them.
http://www.winpatrol.com/