Undo Send is a Gmail Labs feature: http://gmailblog.blogspot.com/2009/03/new-in-labs-undo-send.html . Google Reader also has an ejector seat lever: Mark all as read. This reminds me of the recent Ubuntu window buttons controversy, where the window buttons were moved to the left side of the window. Many pointed out that it is now easier to close the window accidentally while aiming for the menubar. According to the Opposite of Fitts’ Law, the window’s Close button should be placed far away from everything else. By the same reasoning, Maximize and Minimize should also not be too close to Close (as Mikel pointed out above).