I have my master iTunes library hosted on a Powermac (iTunes 10 forever). I use playlists to logically partition the library for sharing with other systems. Because of network instablity (connection losses) I am forced to copy the content of the playlists to the "client" systems. In iTunes 10 on a client system I could connect via Horme Sharing to the master library system, select the appropriate playlist on the master library system and click a button in iTunes which cisplayed the content of the playlist that had not already be copies to the "client" system. I add selections to the playlists from time to time muaking it necessary to update the "client" systems.
With iTunes 11 on a "client" system the above procedure doesn't work because the button to display only those tracks contained in the playlists on the master library system which are not already on the "client" system is no longer available. The button is there if I am displaying the music library rather than a playlist but that is not useful as I don't want a copy of the entire library on the "client" system. I think I could accomplish the same thing by playing around with arbitrary genre names but that is unsatisfying as it loses accurate genre names. I hope that the iTunes 10 function described here will reappear in a future update to iTunes 11. Until them I'll be staying with iTunes 10 on my "client" systems, and of course on my master library system.
To finally end with a question: Does anyone know why this very useful function went away?