If you are not familiar with Spotify — an online subscription based music service with millions of songs in its catalog that offers offline synchronization with the desktop and some mobile devices — there is a high likelihood you are living Stateside. Even though it still not available in the U.S. — really, thanks RIAA — TechCrunch is reporting that Google and Spotify are working together on some sort of partnership that would perhaps build Spotify support right into Android 2.1, and potentially the Nexus One. Details are scarce about whether this partnership would result in a free, ad supported online music catalog for consumers (doubtful) or a subscription based service to compete with Apple iTunes Music Store. Either way, we are keeping our fingers crossed that offline synchronization stays on the table at some level, paid or not. This does make us curious though, would any of you switch to a subscription based service like Spotify if it allowed for offline synchronization? Or is owning/sharing/dominating your MP3 library a complete necessity?