The first company that I've noticed be affected is YottaMusic.
I'm not sure what the difference is between the public and non-public APIs (or how YottaMusic got access to the non-public ones in the first place). But, it's unfortunate, I thought highly of YottaMusic and I think Rhapsody could have learned a thing or two from them. In fact, they should have bought them and leveraged their talent to finally RE-introduce some better community features into the Rhapsody service.
Rhapsody had, in fact, introduced some new community features (music profiles) last year but then rolled them back - rumor is that they way the feature was architected was not able to scale and was straining the whole service. I don't know if this is accurate or not, but I would love to see them make a reappearance. It's been over 6 months since they were yanked. Anyone from Rhapsody want to provide a more detailed update than this one?