The primary use-case that comes to mind here, is if I start playing music with my Spotify account I might like the Tidbyt to go to a responsive Spotify mode (where it only displays the Spotify app) that updates quickly with each song change.
This would allow a default behavior, where when I’m not playing music on Spotify it might default back to my some default application or application page (see feature request about app pages).
We could build priority based on different levels of information. Say I receive a message, or phone call (assuming there was an application for that) it might supersede Spotify or the default set of applications, etc.