title: iOS > "id" vs. NSObject
body: <p>Is there a difference between relating to an <code>Object</code> in a 'Polymorphic' way with the type <code>id</code> than as <code>NSObject *</code>?</p>
  
  <p>In what way is:</p>
  
  <pre><code>NSString* aString = @"Hello";
  id anObj = aString;
  </code></pre>
  
  <p>different than:</p>
  
  <pre><code>NSString* aString = @"Hello";
  NSObject* anObj = aString;
  </code></pre>