Maybe because they are already charging that way, getting premium profit out of their bits, and people paying for them and are mostly happy with the product. I

Maybe because they are already charging that way, getting premium profit out of their bits, and people paying for them and are mostly happy with the product. I mean, if Facebook was charging per wall post and had managed to be massively used as it is today, it would be insane to ask them to go "open bar".