input: [1] Browser (it’s search form history) [2] search phrase computer username [3] Your browser’s search form remembers this search phrase to make your life easier. [4] Indefinite. Usually until you have so many phrases that it prunes the list. Even after that the data is still on your hard drive, recoverable until over-written. [0] 
output: You type your keywords “panda bear sex” in your browser’s search box and hit “enter”.