The people that are most likely to pay are (in most cases) the most loyal users, who visit the site regularly. If those loyal users who push up ad views then move to an "ad free" plan, ad views go down, ad sales team gets sad.
Don't get me wrong, everything about this model sucks -- it's just not as straight forward as it might seem.
Don't get me wrong, everything about this model sucks -- it's just not as straight forward as it might seem.