There has been a bit of a brouhaha lately with regards to guitar compatibility between Rock Band and Guitar Hero III on the PS3. As of now, you can’t use the Les Paul guitar that comes with Guitar Hero III when playing Rock Band (on the PS3). Why? It’s not like they’re very different — and, of course, you can already use Guitar Hero controllers with Rock Band’s 360 version!
It seems that Activision has demanded that Harmonix/MTV Games/EA (the three-headed monster involved in producing Rock Band) pony up for the privilege of using their guitar. This is all, of course, playing out to Harmonix’s advantage in the court of public opinion, but one additional factor makes me think that this will be resolved to Harmonix’s satisfaction. Harmonix still has a very relevant patent on the scrolling note display used in Guitar Hero III — one that this news article suggests was, in fact, licensed by Activision. (I had heard through the grapevine that Neversoft had investigated using non-patent-encumbered ways of showing the notes for the game, but I guess they gave up on that.) The material covered by the patent is pretty critical to the gameplay of Guitar Hero, and after the stellar sales of the third installment, it’s easy to see that Harmonix could use future licensing of the patent as a bargaining chip.
I don’t own a PS3 (or Guitar Hero III — I had just rented it), so I’m not affected by this issue, but it’ll be interesting to see how this all plays out.