Keeping in touch

I have a mobile 'phone which, as a 'phone, is used strictly for emergencies and, until relatively recently, for sending e-mails.  But they cost, and some time ago my grandchildren introduced me to Whatsapp, which is a way of sending messages using the 'phone but which is free.  All the family are part of a Whatsapp group and we can message each other as and when.  Brilliant - but it does make you wonder what the future is for e-mails?  Indeed, what the future is for mobile 'phones, although I think they make their money these days more from people who use them to access the Internet.