The modification of the traditional paper publishing model is going to affect the means whereby revenue is generated from the publication. The academic style journal, relied primarily on subscriptions, with few advertisements - usually relating to job or research offerings, but limited to a few pages.
Revenue is generated by selling both subscriptions and advertising space.
Academic journals revenues are based primarily on subscriptions, these journals are issued 4-6 times per year and often only available to subscribers. Advertising revenue and supporting grants from funding institutions are secondary forms of income, with the availability of the grants decreasing in recent years. The shelf life of these types of serials tends to be very long. Articles in these journals are authored with multiple references to supporting materials and documents. The advent of the Internet as a product of mass consumption has changed this way of thinking.