I can't find the citations right now, but there was a recent study done through Elsiver's website. The group got a hold of the servers for Elsiver and took a look at page views. They wanted to know what the rates of papers being read was. It was... disheartening. They found that ~46% (again, not sure here as I can't find the source) of papers will never be looked at outside of the authors, reviewers, and the editors. The articles are not only never downloaded, but the pages are never even loaded. The stats were, to me, confusing, but hey that is what peer review is for. Still, if you take this paper (that I can't find now) to be true, ~half of all papers are effectively lecturing into the void. I admit, I drank a bit after reading that one.