(Quick context: I'm running iTunes 9 on Windows XP.)
In the Options tab of the iTunes Get Info box, there's an option for selecting a track's "Media Kind". Under iTunes 9 the list of options are Music, Podcast, iTunes U, Podcast, and Voice Memo. (And I'm pretty sure some of those options are new in 9.)
My question then, is this: what does setting the Media Kind actually do for you besides having the given track appear in the respective library tree on the left pane?
Does iTunes just treat this as a kind of "meta-genre" to be searched and filtered against, or is there an actual feature difference?
To put a specific example out there: my rip of my Hitchhiker's Guide CD is currently under Music with a Genre of Radio Show. Is moving that to a Media Kind of Audiobook or Podcast going to gain me anything?