(1) To press the mouse button twice in rapid succession. Double clicking was prevalent in the early days of graphical interfaces when it was thought that the extra click was necessary to ensure that the user really wanted to perform the function. However, the convenience of the single click Web hyperlink caused many applications to later be changed from double clicking to single clicking.

(2) (DoubleClick Inc., New York, www.doubleclick.com) A Web ad serving company that began in 1996. DoubleClick is perhaps the most widely known organization that delivers Web advertising. Its growth expanded well beyond ads into rich media, search, video and all kinds of digital affiliate marketing. See adserver.