There's a fair bit of tech below the surface in this app, for stuff like song discovery in the background and getting track metadata. Happy to answer questions about that stuff.
Geekwire posted about it: http://www.geekwire.com/2011/tunebox-listen-music-dropbox-ac...
30s demo video here: http://yearofcode.com/tunebox
I'm also curious - how does it fetch metadata for songs? It looks like it all happens on demand from the app. I've got about 40GB of music in Dropbox so I imagine this might be a slow / API call intensive process.
My wishlist: I would like to download some albums for offline use and I would like to have the app index more than 1000 songs.
But don't take these suggestions as criticism. I love your app and it is already extremely useful!
To work around the 1000 songs thing: tap the Browse tab, browse to folder with songs that weren't included. Wait a second, then go back to Artist/Albums/Songs, they will be there and the app will know about them unless you sign out (which makes it forget everything).
The limit is based on what the Dropbox API can return, but Tunebox itself is designed to be able to index a lot of music.