title: How can I prevent spam while letting users email content to their friends?
body: <p>I'm working on an app (in PHP &amp; JavaScript) that lets users generate content (short stories), and I want to add in a "email this to your friend" button.</p>
  
  <p>I'm worried, though, that this could be used to send spam.</p>
  
  <p>What are some things I could do to prevent that from happening? I am thinking:</p>
  
  <p>1) The user must confirm their own personal email address before I send it
  2) I have a hidden field somewhere that bots would fill in</p>
  
  <p>What else should I do?</p>
  
  <p>Cheers</p>