Bit9

What is Application Whitelisting?
It's antivirus turned on its head. It's looking through the opposite end of the lens. It's the opposite of blacklisting.
Instead of playing the 1980's game "Whack a Mole" where the mole keeps popping up and you're constantly behind trying to bop the little toy on the head - people do odd things for fun - you decide who are the good moles and then open the holes for only those good ones.
Instead of putting US air marshals on every airplane to look for the bad guys who are already on, you secure the gate better and let only the good guys onto the plane.