Every time you open a browser to view a Web page, that information is stored on your computer -- whether you're shopping online, checking movie listings or catching up on the latest news.

Windows operating systems store this material in Temporary Internet Files or "cache."  Web pages may store bits of information about who you are in files called "cookies" on your computer.  Your Web browser will store a list of Web sites you've visited and places you've gone in a history file in your computer -- thus creating your digital footprint. 

Even if you're not online, programs will store histories of the files you've opened, played, or viewed.

Cookies are created to recognize users when they return to a Web site; they make it possible to offer customized content to a user.  Even though cookies make Web use quicker and more convenient, they can be a threat to your privacy if they store sensitive information like your name and password on protected login pages, preferences, account information, and choices you have made on the site.  So, even if you clear browser history, cookies -- like a map -- can show your surfing preferences, habits, passwords, and so forth.

Even if the cookies don't contain such information, they clearly show that you visited the sites from which they came.