• a (flag): authenticated user – someone who is a registered user on the site
  
• k (flag): known – if a visitor has submitted a form with their email address
  
• s (scalar): score – overall value of the visitor. Automatically updated with event and goal values.
  
• l (scalar): lead score – The likelihood of a visitor becoming a customer
  
• g (list): groups – categories for tagging visitors
  
• i (vector): interests – categories with levels