(The 'nonatomic' isn't related to the retain/no-retain semantics, but most properties are declared nonatomic, as atomic properties have some locking overhead.)
On a side note, a discussion of iOS/Mac memory management isn't very useful if it doesn't talk about how autorelease pools work.
The same thing applies to "copy" properties. If you do "self.foo = bar;" when foo is a copy property, you have taken ownership of that object, and need to release it later (hopefully by doing "self.foo = nil;".
On the topic of properties, I also find it helpful to define the property and variable to have different names (e.g., NSString _foo; for the variable and @property (nonatomic, copy) NSString foo; for the property). When mapped through @synthesize foo = _foo;, it avoids confusion about the memory management necessary for a particular value.
No no no no no... That is absolutely incorrect. Only properties declared "retain" do that.
(The 'nonatomic' isn't related to the retain/no-retain semantics, but most properties are declared nonatomic, as atomic properties have some locking overhead.)On a side note, a discussion of iOS/Mac memory management isn't very useful if it doesn't talk about how autorelease pools work.