title: Passing email address in query string
body: <p>This question is more theoretical.
  Is it save to be passing email address in query string like:</p>
  
  <pre><code>www.something.com/?email=person@domain.com
  </code></pre>
  
  <p>I am using this in one project, but i would like to know what are the downsides. Cause some big services are avoiding this, for example Gravatar wants you to convert email address into MD5 hash and then pass it in query. </p>
  
  <p>Thanks for explanation</p>