How do you define user's "join date"? Is it the first time you saw the user?
For that matter, how do you identify the user? If the user logged in from two different machines, does it count as one user or two?
For that matter, how do you identify the user? If the user logged in from two different machines, does it count as one user or two?
It counts as two, since by default we identify users with first-party cookies. We offer a heap.identify() API call that can be made to associate multiple devices with one identity.