Most web browsers have a feature that will automatically fill in your home address, phone number, email address -- and even credit card number -- when the browser detects that you're typing personal information into a form. This means your information is stored on your computer. When it comes to securing this information, you have to take charge and set your privacy preferences in the browser.

For example, Mozilla Firefox browser allows you to create a master password that you have to input before your browser can remember (and auto-fill) your username and password for a web site. Also, under Preferences > Privacy, you can select "Always clear my private data when I close Firefox." In this case, when you quit the browser software, any private information you entered while using it will be erased.

In Internet Explorer, you can adjust your privacy settings by going to Preferences > Forms > AutoFill.