>Look if it is saved in the smartphone's address book, why does it matter if it is email or a phone number. Because when people interact with each other in in

>Look if it is saved in the smartphone's address book, why does it matter if it is email or a phone number. Because when people interact with each other in informal situations, it's the phone numbers that are shared. Not email addresses. Thus, email addresses are often not in the Contacts app at all.