title: Voting for items via facebook like?
body: <p>I have a friend who wants to run a weekly contest where users can vote on their favorite pictures. He wants users to "Like" a photo in order to vote for it. Is this a reasonable mechanism for this action? Will this work? Is there a reasonable way to get the vote numbers out of facebook?</p>
  
  <p>Facebook <a href="https://developers.facebook.com/docs/reference/plugins/like/" rel="nofollow">indicates</a> that the Like number on a button is the sum of:</p>
  
  <pre><code>* The number of likes of this URL
  * The number of shares of this URL (this includes copy/pasting a link back to Facebook)
  * The number of likes and comments on stories on Facebook about this URL
  * The number of inbox messages containing this URL as an attachment.
  </code></pre>
  
  <p>I'd want to make sure that people would only be able to vote once, and not message the URL to a lot of friends in order to gain votes.</p>
  
  <p>What are the downsides and/or implications of building it this way versus building a more traditional polling system?</p>
  
  <p>Thanks!</p>