''This is something done billions of times each day '' ThinkingOutLoud.DonaldNoyes.20121003.2359
-----
As such it probably is third, behind SingleClick and MouseMove as in the TopTen of Computing UsefulUsableUsed things.

It is particularly useful where in the SmartDevices in extensive use today, where the importance of the index finger and the thumb has allowed actions formerly performed on the Desktop and Laptop computer by mouse and keyboard action to be supplanted by TouchAndMove.  The DoubleClick or Double Tap on some devices is used for selection and zoom functions. (more quickly than PinchAndExpand one does with the thumb and index finger) 
----
Related
Included in other things possible in the future incorporating technology of motion and attitude sensors and Gps and clever usage of them. (note motion need not be of the device only, it might also be of what might be sensed by the cameras (multiple) included in many devices today and tomorrow, or in sounds or lack thereof} (attitude might also include a time sense of attitude image change, where leaving a device in an unchanged and inactive state might also trigger actions such as deactivating or putting to sleep the device, or causing it to perform automation actions being based upon ItDepends.

----
CategoryFuture