For instance, Why is the "Top Music Free iPad Apps" in iTunes for Mac so different from "Categories -> Music -> Most Popular" in iPad's App Store?
Does anyone know what's the deal with these charts?
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My guess is they use a different sorting criteria. The "Top Music Free iPad Apps" in iTunes is most likely the list with the apps which are downloaded the most.
Most popular would be the list of apps which is the most popular in search results or page visits.
I don't have any proof to support this theory (I'll look for it), but this is my guess.