"A subscription implies I get something that normal users don't get." Fair enough - but there are very, very few value creating engines that can feasibly exist

"A subscription implies I get something that normal users don't get." Fair enough - but there are very, very few value creating engines that can feasibly exist in such a context. Wikipedia is one. Stackoverflow probably could not. Someone mentioned it creates 'billions' in value, well, that's probably not too far off. There's nothing wrong with people paying for things. But to your point - it would be nice to find a way to do intelligent price discrimination. Students, hobbyists get it free, other entities can pay. etc.. I don't think that would work for Stackoverflow either because there is an inherent 'open-ness' that it needs ... that said, again, there's nothing wrong with paying for things.