Ubuntu, the popular Linux distribution, has been experimenting with a number of interface designs lately. Today, the project's founder Mark Shuttleworth announced that the next major version of Ubuntu, 12.04 LTS, will feature a replacement for the menu bar. This "Head-Up Display" (HUD) is more akin to well-known Mac utilities like QuickSilver and Alfred. The idea here is to eventually replace the global menu in Ubuntu's Unity interface – which is similar to the menu bar at the top of the screen in OS X – with a more keyboard driven "vocabulary UI" approach that can understand the user's intent without having to search through an application's menu system.
Ubuntu 12.04 will still feature traditional menus, but introduce the HUD as an alternative to the current design.
Shuttleworth notes that Ubuntu's user testing found that most users spend a lot of time navigating menus, either to learn about a program's functionality or to take an action. Menus, says Shuttleworth, serve two functions: "They act as a standard way to invoke commands which are too infrequently used to warrant a dedicated piece of UI real-estate, like a toolbar button, and they serve as a map of the app’s functionality, almost like a table of contents that one can scan to get a feel for ‘what the app does.’"
In order to improve on this concept, Ubuntu wants to create a system that allows users to express their intent. Current menu-driven systems, says Ubuntu, require users to read too much, even though they already know what they want to do. They are hard to use from the keyboard (unless you already know an application's shortcuts) and "force developers to make often arbitrary choices about the menu tree."
The HUD concept allows users to simply say what they want to do and then do it. Thanks to fuzzy matching and its ability to learn and then prioritize commands you regularly use, this approach should give advanced users an advantage over the menu system.
One problem this approach doesn't solve, though, is giving users an idea of a program's capabilities. At least with regular menus, you can figure out what an app can actually do by just browsing through the menu tree.
Ubuntu has been widely criticized for its move to the relatively non-standard Unity interface. This announcement today will surely have its critics as well, though I have to give Ubuntu some props for trying relatively radical new things – something more established mainstream companies like Apple and Microsoft can't really do at this point.