[borism]

you can't tell if a new sale is someone newly adopting your platform, or just someone that is moving from one phone to another while remaining on your platform

I'm sure Google or Apple can tell, since activating Android or iOS involves linking it with Google or iTunes account.

[pyre]

But new sales are usually numbers in terms of new phones that people bought, not numbers on how many of them just activated their phone for the first time. Buying your phone is a sale. Activating your iOS or Google account is not.