When going to a .com domain in Google Chrome, you don't have to type the www. or .com because this handy keyboard shortcut can do it for you. Just press Control+Enter on any platform (it's even Control+Enter on a Mac) and Chrome will take care of the rest.
You can do this in Firefox, too, but it's not just limited to .com. Either way, this can save you milliseconds of typing several times per day.
Shortcut of the Day highlights a great shortcut on various platforms from the desktop to mobile devices to the web. You can find more shortcuts here.