"Many of the specific examples provided in Lev Manovich's discussion of new media's variability suffer from an imprecision that leaves unclear just how the Principle of Variability ought to be properly applied when thinking about new media objects" This article relates to the Manovich reading and variability.
"Lev Manovich sites the five principles of New Media as Numerical Presentation, modularity, automation, variability, and transcoding. It is the second category, modularity, with which I seem to take issue" Blog entry, in which the other takes issue with Manovich's "modularity" category.
If you had trouble understand the class reading or thought it was too dumbed down here is another article by him that covers the same topic in less words but more in depth.