I very much doubt that this is the best answer. We are using a model that pre-dates the Internet to cover the expenses of site content. Given how unpopular it is for the readers of print publications and viewers of television, it seems a mistake to consider something so obtrusive the best available solution. While I don't as yet have a better solution, the fact that no real research into alternatives has been done makes me believe that there has to be a better available model.