title: Prevent users from starting multiple accounts?
body: <p>I know that in the end it, can't be done.</p>
  
  <p>But, what are the options to:  </p>
  
  <p>&nbsp; a) limit the options for persons to create multiple accounts,<br>
  &nbsp; b) increase the chance of detecting multiple accounts / person  </p>
  
  <p>for a blog-like web service?<br>
  (people can sign up for their own blog)</p>
  
  <p><strong>Update:</strong><br>
  I think the 'limit the options' has been answered nicely. (there is no reliable method, but we can raise the bar)<br>
  However, I would still like to know what other options there are to detect multiple accounts?</p>