The article complicates things by talking about 'autorelease' and '@property'. Neither of these concepts are necessary in understanding memory management in ObjC, they just add convenience to it.
autorelease was added at the same time as the retain/release. @property, on the other hand, came much, much later and is entirely separate.
Obviously it's something any Cocoa developer would want to learn, but it didn't seem necessary in an article trying to prove how basic memory management in ObjC is.