title: Paypal IPN - How does it work?
body: <p>I need a brief explanation on how Paypal IPN works. Not anything in details just the basic stuff.</p>
  
  <p>How should I set my HTML variables and how should I get the data to verify the payment from Paypal? This is all I need to know and I can't find a quick explanation on this one somewhere. </p>
  
  <p>If possible, show me some code lines too, would definitely help.</p>
  
  <p>Thanks.</p>