Opinion: On WhatsApp, when were you 'last seen' at?

What about the service being charged every time someone opens the app? — School photo created by freepik - www.freepik.com

A friend asked me the other day: "Is it a good idea for WhatsApp to become a paid-for platform?"

"Not just good, but brilliant," I said. "I have my own reasons for thinking so — what's yours?"