Response to GNUstep: Open-source, Object-oriented, Cross-platform Development Environment

GNUstep is a mature Framework, suited both for advanced GUI desktop applications as well as server applications. The framework closely follows Apple's Cocoa APIs and is portable to a variety of platforms and architectures.
Reading this comment really brought back memories of being an Objective-C developer in the early MacOS X days. One thing I lamented in those days was that whatever I wrote was stuck on the Mac and GNUstep gave me hope that it didn't need to be.

High school me used to think how cool Objective-C and Cocoa was and how it was the future. And thanks to the iPhone, for a long time I was right.

But the web won the war for Cross-platform development and most days I'm glad it did.