title: Best way to track emails - UUID vs ID number
body: <p>need to track 1 million email addresses within our organisation for marketing and customer response. It has been decided to develop in-house.</p>
  
  <p>having done a little research into what others are doing I have noticed that all seem to use uuid (guid) for tracking. Is this the best way to track email activity?</p>
  
  <p>Any other advice before we get cracking?</p>