At the Ubuntu Developer Summit (UDS) today in Florida, Ubuntu founder Mark Shuttleworth announced that the Unity shell will become Ubuntu's default user interface across both the desktop and netbook editions. Unity, which was introduced as the new netbook interface in the recent Ubuntu 10.10 release, will arrive on the desktop in Ubuntu 11.04 next year.
Shuttleworth described desktop adoption of Unity as the "most significant change ever" for Ubuntu. He also acknowledged that it is a "risky step" and that much work remains to be done to prepare for the transition. The move reflects Ubuntu's growing divergence from the standard upstream GNOME configuration and effort to differentiate itself with a distinctive user experience. During the keynote, Shuttleworth emphasized that Ubuntu is still committed to GNOME despite the fact that it will ship with Unity instead of GNOME Shell. He contends that diversity and competition between different kinds of GNOME environments will encourage innovation and benefit the GNOME ecosystem.
The decision to ship a custom interface in Ubuntu is going to be controversial. Critics in the upstream community are already expressing disappointment with what they view as a move to fork the desktop. It's worth noting, however, that Canonical isn't the first company to build a unique user experience for GNOME that deviates from the standard upstream user interface stack. Intel also similarly produced a custom shell with the Clutter that is used on the MeeGo platform. Canonical's deviations from the upstream configuration receive closer scrutiny because Ubuntu's popularity among Linux users makes the distribution a king-maker on the Linux desktop. Canonical's decision to ship Unity could deeply marginalize GNOME Shell.
The diverging desktops could pose some challenges for GNOME application developers who will have to support two different sets of desktop integration features. I discussed that issue with Shuttleworth after the keynote to get his perspective. He pointed out that developers are already supporting Ubuntu's indicator system and other custom integration points without much difficulty. He is confident that fragmentation challenges for application developers can be avoided by working through FreeDesktop.org to ensure that desktop integration mechanisms are standardized and interoperable between environments. As an example, he highlighted the collaboration that occurred around the Media Player Remote Interfacing Specification, the protocol that Ubuntu uses to facilitate communication between music players and the desktop's new audio indicator menu in Ubuntu 10.10.