Finally, Android devices will be sporting some sort of uniform other than their touch sensitive buttons. What this actually means is that the default ‘Holo’ theme that Android 4.0 uses will be required in all devices that have access to the Android Market. This meaning that Touchwiz, Sense UI, and Motoblur will have to curve their appearances to fit the feeling of the UI, and 3rd-party app developers have the option of designing their apps in Holo style or the style of the manufacturers.
Google’s move doesn’t kill the skinning of Android devices completely, but it allows for the real light of Android’s design to shine through consistently for once, even if it’s only a set of widgets and design elements. Via: Google