App Hide, as the name suggest is a program to hide unnecessary windows on your desktop and thus save space. It can hide the window of any program using a keyboard shortcut that, moreover, can be customized to fit your own needs. To do this, simply add the name of the windows involved in its interface. This tool is useful in many situations such as to quickly hide your chat software.
App Hide is a free and works with both Mac OSX with Windows operating systems.