title: Difference between binary string and ordinary list
body: <p>I'm new to erlang, and in erlang shell, i typed below expression:  </p>
  
  <pre><code>A= &lt;&lt;"abc"&gt;&gt;.
  B="abc".
  </code></pre>
  
  <p>I want to know the differences between <code>A</code> and <code>B</code>, and their general usage,
  Also why below expression is not correct:  </p>
  
  <pre><code>C=&lt;&lt;abc&gt;&gt;.
  </code></pre>