title: What does "Separate source and build directories" mean?
body: <p>I am trying to use Sphinx for the first time. I am running <code>sphinx-quickstart</code>, but don't understand the first question being asked:</p>
  <pre><code>&gt; Separate source and build directories (y/n) [n]: 
  </code></pre>
  <p>What does this mean? What difference does it make whether these directories are separated or not? How do I know which one to choose?</p>