Matt Yglesias endorses a complaint by John Holbo: Kindle doesn't show page number so it complicates the job of creating footnotes for scholarly articles. Seems to me there's a simple cure: adopt a standard which adheres to the following format: [version of publications--Kindle, Google Book, etc.][search by Google, Kindle, whatever][date searched][number of result].
The point is, after all, not to specify the page number, but to allow someone coming after the writer to reproduce the writer's results, just as a scientific experiment needs to be specified in enough detail to allow reproduction. So if you specify a search engine and a text, and the terms you used to reach the material, that should be quite adequate.