First up, it has a feature called Identify, which is basically a Shazam or SoundHound clone: it listens to the track in question, then tells you what it is. It does differ from the aforementioned apps in one way, however - it offers continuous mode, where it will scan a series of songs, returning results for each one. I'm not entirely sure how you may actually use that feature, but I guess it's still pretty neat.
And then there's Smart Shuffle... apparently this crawls into the limbic system in your brain to judge what your mood is and create a playlist custom-fitted to how you're feeling at the time. There's no need for the usual thumbs-up or star-rating systems; it just knows what you want to hear... creepy, right? It actually claims that it "takes cues from your past listening behavior" to create said playlist - but I like my explanation better.
Yahoo! Play is available for free in the Android Market, and you can grab it by hitting the widget down below.
[Yahoo! Mobile Blog via IntoMobile]