What is the difference between Delegate & Action in C#
<p>If I searched I will definitely get examples of showing what is a Delegate and Action. 
I have read the basic books giving examples of delegate. </p>

<p>But what I want to know is their use in the real world. Please do not give Hello World example or the Animal class they are far too basic</p>

<p>For e.g. :</p>

<ol>
<li>What are the difference between them</li>
<li>When to use a delegate or action</li>
<li>When not to use a delegate or action</li>
<li>When they can be an over kill</li>
</ol>
