Shazam is one of those nearly magical apps that has been around since 2008. If you hear some music, you use Shazam to identify it by just holding it up and allowing the app to match it up with its database. The service makes money off partnerships and a sort of subscription services for its hardcore users.
I've noticed the Shazam logo on a few ads here and there, and they've had some high profile partnerships like American Idol, where using the app will bring up song lists and iTunes links. Shazam now lets you tag any TV show on any channel, and will tell you who the actor is or what song is playing. There's even support for sports scores, although local programming won't register.
Shazam will be monitoring stations and updating constantly, no small feat for an app which now claims 250 million users as its base. That's one of the most-downloaded apps of all time. Personally I like Soundhound (particularly the scrolling lyrics feature), but Shazam's TV utility is a fun twist.