How to Use Gatekeeper Security in OS X Mountain Lion

Not only do people need protection from malware, they need protection from themselves. That's where Gatekeeper comes in, a new feature of OS X Mountain Lion. By default, Gatekeeper lets you download apps from the Mac App Store or from developers who have a Developer ID. However, Apple recognizes that people who are power users will want more control. Here's how to use and fine tune Gatekeeper.