|It's the keyboard shortcut for the "search page" function|
Did you know that hitting control and "f" will open a search bar at the top of your browser page. Type "control" and "f" then type in what word you're looking for and hit enter. It will find every instance of that word and tell you how many there are. It's great for reducing the time spent searching for specific information on a huge web page.
For example, Blogger continues to insert "background: white" html code into my blog pages which causes some of my text to be black on white. In the middle of my black on green page. This annoys me. This annoys me a lot.
Solution: in my edit interface, I go to the html tab, hit "control f" enter "white", hit enter and remove every last one of those spurious buggers.