Planning on using a public computer? Do you have family members or children who also use your machine? You may not want them to know you are planning a surprise trip to Disneyland, that you are concerned about a that mole on your leg or that you belong to the kitten of  the month club.  Browsing in private mode keeps the pages that you have visited out of the history list.  This keeps users that come after you from checking on the history list to see where you have been.

Different browsers have different names for private mode. In Safari and Firefox it is called, Private Browsing. In Chrome it is called Incognito.  Check out the links to find out how to browse privately in your browser of choice.