title: Proper MIME media type for PDF files
body: <p>When working with PDFs, I've run across the MIME types <code>application/pdf</code> and <code>application/x-pdf</code> among others. </p>
  
  <p>Is there a difference between these two types, and if so what is it? Is one preferred over the other?</p>
  
  <p>I'm working on a web app which must deliver huge amounts of PDFs and I want to do it the correct way, if there is one.</p>