title: Verify that email domain exists
body: <p>Does anyone check the domain of an email address as part of their verification steps? eg. Confirm that gmail.com exists if the user specified blah@gmail.com as their address.</p>
  
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  <p>I should note that in my webapp an existing user can forward invites to their friends. I have no need to verify those invites at all. Rather, I just want to warn my user if a typo etc. may be sending an invite to the wrong person. Is this even worthwhile to do?</p>