EdgeCase improves your multiple monitor productivity by restricting your mouse cursor to a single screen.
The app prevents you from ever accidentally losing your cursor into a rarely-used secondary display, or from overshooting as you flick to an OS X hotcorner or the menu bar.
When you do want to switch to another screen, EdgeCase provides several shortcuts that allow you to cross screen edges manually. Simply perform a 'bounce' gesture, wait for ½ second, or hold a hotkey. Your cursor will then move into the next screen freely.
☞ "I’ve found EdgeCase to be useful on my multiple-display setup." - Dan Frakes, Senior Editor at Macworld
☞ "A pretty good solution to this problem." - Marco Arment, Creator of Instapaper (dot com)
☞ "Once you have more than one monitor, instead of hitting the edge, the mouse moves to the other screen. EdgeCase solves this problem. With EdgeCase, the edge returns, and works as if you only had one monitor." - Lukas Mathis, Ignore the Code