title: Magento Model vs Block vs Controller etc
body: <p>I've looked and looked on google, but can't find a single site explaining what each of the 6 module subfolders are.  I'm usually really good at finding things on google, but this one has constantly come up with nothing.</p>
  
  <p>Could someone explain the differences between each of the subfolders in a Magento module (Block, controllers, etc, Helper, Model, sql)?</p>