Windows: Want to protect your screen from the nosy eyes of colleagues peering over your shoulder? AntiSnooper is a free program that blurs out any window you want it to, as long as your mouse is focused elsewhere.
Start the program and it will show you all your currently running tasks and windows. You can choose to activate AntiSnooper for any of them. In the options, you can set a protection timeout, which is the number of seconds your mouse would need to be focused away from that window to start AntiSnooper's effect. The effect can be to blur the text or start an in-app screensaver for just that window.
Your preferred settings can be saved as a profile to quickly add any program to AntiSnooper, and you can have multiple profiles for different apps.