OK so I’ve been playing around with Genius and here are my initial thoughts / experiences:

– If you’ve got a lot of indie catalogue in your iTunes catalogue (and I do) it reveals just how may gaps remain in the iTunes Music Store catalogue. The “Genius is unavailable for the song”… came up on nearly half my requests. Over 80% of my dance music requests weren’t matched with a Genius list.
– There’s still some funkiness in the app. For example “Love Man” by Otis Redding is available on 5 different albums on the iTMS yet no Genius playlist is available.
– I discovered some hidden gems I’d forgotten about in my collection (“Lazy Eye” by Silversun Pickups)
– I discovered some embarrassing musical secrets – I was horrified to learn that I had Cascada in my collection – turns out it was in the midst of a Brits Awards compilation that was given away at the event and to which to my shame I’ve never listened to. I didn’t buy Cascada though, phew!
– Some links are just bizarre – e.g. “Wet N Wild” by Kim (a dirty breaks track) got me to “Beautiful” by Christine Aguilera, and as the 3rd track in the list. Damn there goes another embarrassing secret.
– Some links are unacceptably shallow. e.g. “Hey Scenesters” by the Cribs brought me up 4 other Cribs songs. So 20% of my 25 song Genius playlist were just songs form the same band.
– The subtlety of sub-genre isn’t well catered to yet. (Though that should come as Genius uploads gain momentum.) e.g. I have much more dance music than is good for me in my collection (i.e. lots of sub-genre depth to drive Genius) but “Domination” by Way Out West (old school trance track) pulls up “Another Chance” by Roger Sanchez (mainstream poppy dance smash hit). That might work for someone who has a passing interest in “electronica” but not for anyone with specific dance music tastes.
– It seems to be good at the old stuff. E.g. Paul Stanley linked straight onto Kiss, Deep Purple, Guns ‘n’ Roses etc.
– And to finish on a positive note, sometimes it gets it right, and when it does, it gets it *really* right. “Loretta’s Scars” by Pavement pulled up a whole host of personal favourites from old school shoe gazer bands like Ride and Slowdive through to new faves from modern-day Pavement-esque acts like the Hold Steady and Arcade Fire (though not quite sure what Cream were doing in there). And whilst I’m at it, how on earth weren’t the Strokes in that list. Those guys should be paying copyright infringement fees to Pavement…but I digress..

So in conclusion, an app that shows a lot of promise and may yet become the centre piece of a new music service. But right now needs not only more users to upload their music data but also some tweaks to the algorithms.