I only use the search when I know what app I'm looking for. Wouldn't that would drive up the numbers artificially -- as I had the intention of downloading the app before I began searching.
I wouldn't think so, not if they're saying a percentage of all downloads come from search, as opposed to a percentage of all searches lead to a download.
But searching is the only way (sane) people find anything on the App Store. When was the last time you browsed the store until you found the cool new app you just read about?
Whenever I use the App store, I'm on a mission. But it's also a mission to get free stuff, so maybe I'm not even part of the equation.
