Not only did the renaming serve to differentiate the new default behavior of classes within the OpenStep API, but it allowed code that used Object—the original base class used on NeXTSTEP (and, more or less, other Objective-C class libraries)—to co-exist in the same runtime with code that used NSObject (with some limitations). The introduction of the two letter prefix also became a simplistic form of namespaces, which Objective-C lacks. Using a prefix to create an informal packaging identifier became an informal coding standard in the Objective-C community, and continues to this day.
