Corner clicking is the technique of setting up a button press to be located at any corner of the user's screen (varies depending on the activity) in order to quickly click when necessary. It is done as a method of circumventing the need for precision in certain in-game scenarios. This is effective because it requires minimal skill to drag a cursor to any corner of a user's screen in comparison to any other on-screen location. It should be noted that many Windows operating systems by default have the task bar located at the bottom of the window, but it is movable.
In the case of logging out a user would drag their game window so that at the bottom-right corner of their monitor the logout button can be pressed. With the introduction of the world-hopping feature it is possible to leave nearly the entire window visible with this set up. This is especially useful in Wilderness situations where a player cannot properly defend themselves.
The primary use for this is when using the spell Superheat Item. To do this a player places their game window so that the bottom-right corner of their screen contains the last ore in their inventory. With this set up, simply click the Superheat spell and quickly drag the cursor down and to the right and click.