[chosenbreed]

Okay. But not so long ago people had to pay for WhatsApp, no? Has the user base grown tremendously since it became free (i.e. because it became free)? One of the points made earlier is that before being bought by Facebook WhatsApp was a profitable operation. If that was the case then there is clearly an argument for having a relatively low cost subscription based offering...

[thirdsun]

I'm not sure if they actually ever enforced their payment/subscription. I certainly haven't been charged, but I was a user before that started if I remember correctly.

[krageon]

It didn't "become" free. It has always been free for some significant fraction of the userbase. As was mentioned repeatedly all over the comments here, many people have never seen the payment screen at all.