> Maybe a large enough population pays $4/month and can thus subsidize some part of the population That's how WhatsApp started to fund itself, I remember there

> Maybe a large enough population pays $4/month and can thus subsidize some part of the population That's how WhatsApp started to fund itself, I remember there being a nominal annual charge ( £1 ) for some users but not for all. There didn't seem to be any obvious rule as to who was pinged to pay-up, perhaps it really was random. But that was discontinued after they were acquired.