title: What is Extract/Transform/Load (ETL)?
body: <p>I've tried reading the <a href="http://en.wikipedia.org/wiki/Extract,_transform,_load" rel="noreferrer">Wikipedia article for "extract, transform, load"</a>, but that just leaves me more confused... </p>
  
  <p><em>Can someone explain what ETL is, and how it is actually done?</em></p>