This is also what was described by John Gruber: Users have three choices which type of apps can run on Mountain Lion: * Only those from the App Store * On

This is also what was described by John Gruber: Users have three choices which type of apps can run on Mountain Lion: * Only those from the App Store * Only those from the App Store or which are signed by a developer ID * Any app, whether signed or unsigned The default for this setting is, I say, exactly right: the one in the middle, disallowing only unsigned apps. http://daringfireball.net/2012/02/mountain_lion http://daringfireball.net/2012/02/mountain_lion