Well, yes, it is popular, and yes, it is popular today because Apple uses it, but still, people are using it in projects that don't have much to do with iOS/OS

Well, yes, it is popular, and yes, it is popular today because Apple uses it, but still, people are using it in projects that don't have much to do with iOS/OS X, such as Web Frameworks (Frothkit, Bombax) and client-side MVC (Cappuccino). In this aspect it's similar to C#, and Mono, I think, but in a much smaller scale.