Apple’s Mac operating system, OS X Mountain Lion, is scheduled for release in July. The next OS includes a feature called Gatekeeper that can be configured to allow only applications from the Mac App Store to run. Apple requires that all apps distributed through the App Store must only be updated via the stores own update mechanism. Apple and developers need to be diligent about ensuring that versions of software are kept up-to-date, especially when new versions contain security improvements. Some versions of applications in the Mac Store have limited functionality compared to their non-App Store counterparts.”]
Source: https://nakedsecurity.sophos.com/2012/06/21/mac-app-store-gatekeeper-security/