title: Understanding the transclude option of directive definition?
body: <p>I think this is one of the hardest concept for me to understand with angularjs's directive.</p>
  
  <p>The document from <a href="http://docs.angularjs.org/guide/directive">http://docs.angularjs.org/guide/directive</a> says:</p>
  
  <blockquote>
    <p><strong>transclude</strong> - compile the content of the element and make it available to the directive. Typically used with ngTransclude. The advantage of transclusion is that the linking function receives a transclusion function which is pre-bound to the correct scope. In a typical setup the widget creates an isolate scope, but the transclusion is not a child, but a sibling of the isolate scope. This makes it possible for the widget to have private state, and the transclusion to be bound to the parent (pre-isolate) scope.</p>
    
    <ul>
    <li>true - transclude the content of the directive.</li>
    <li>'element' - transclude the whole element including any directives defined at lower priority.</li>
    </ul>
  </blockquote>
  
  <p>It says <code>transclude</code> typically used with <code>ngTransclude</code>. But the sample from the doc of <a href="http://docs.angularjs.org/api/ng.directive:ngTransclude">ngTransclude</a> doesn't use <code>ngTransclude</code> directive at all.</p>
  
  <p>I'd like some good examples to help me understand this. Why do we need it? What does it solve? How to use it?</p>