title: Cross device user tracking
body: <p>Let's say I have a facebook campaign displayed on mobile device, which leads to conversion (android application installed, it's deeplinked). Now the same user opens my webpage (with facebook pixel) on his desktop computer and buys some stuff there.</p>
  
  <p>I would like to track that conversion was initiated by that campaign - with some external tool (mixpanel, exponea...). Is this possible? Is facebook pixel the right way to achieve this?</p>
  
  <p>The user is not logged in, just on facebook on his device and his desktop.</p>