Look and feel play a big part, even once you get things to compile. A "Native" OS X application should (largely) follow the Apple Human Interface Guidelines[1]

Look and feel play a big part, even once you get things to compile. A "Native" OS X application should (largely) follow the Apple Human Interface Guidelines[1], but the same application following those guidelines in another operating system would probably feel out of place. Hence the need to "port". This applies less to command line tools etc, since they don't need a GUI and can just follow POSIX CLI standards to fit in. [1] http://developer.apple.com/documentation/UserExperience/Conceptual/AppleHIGuidelines/XHIGIntro/chapter_1_section_1.html http://developer.apple.com/documentation/UserExperience/Conc...