Sony's reportedly thinking about pulling out of iTunes entirely in order to focus on their cloud-streaming Music Unlimited service. This might be a reaction to Apple's fight with Sony's Reader app in the App Store two weeks ago, or it might be part of a larger plan.
On Sony's side, the guess is that they won't be licensing music or Sony's PlayStation games (either NGP games or Xperia Play games, which is an Android-based portable phone/gaming system) to Apple. And if Sony pulls out, it's a reason for other music labels to pull out too.
It's not unheard of for one or more labels to test iTunes by withholding content, often using Amazon's music service as a way to gain leverage against Apple. Apple itself is working on a cloud-based streaming service as well.
Seeing as iTunes is the number one music outlet in the US, Sony pulling out entirely still seems unlikely, especially with the number of iOS devices Apple is selling now. But all of this could just be leverage for Sony to get a better deal licensing its content to Apple. [The Age]