The Ubuntu plan is to eventually have this heads-up display, which was developed in-house, to "ultimately replace menus in Unity applications." The Ubuntu HUD is about a way for the user to express their intent and to then have the HUD respond appropriately based upon the interpreted intent.
From Mark's blog post, "Menus serve two purposes. 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’. It’s command invocation that we think can be improved upon, and that’s where we are focusing our design exploration. As a means of invoking commands, menus have some advantages. They are always in the same place (top of the window or screen). They are organised in a way that’s quite easy to describe over the phone, or in a text book (“click the Edit->Preferences menu”), they are pretty fast to read since they are generally arranged in tight vertical columns. They also have some disadvantages: when they get nested, navigating the tree can become fragile. They require you to read a lot when you probably already know what you want. They are more difficult to use from the keyboard than they should be, since they generally require you to remember something special (hotkeys) or use a very limited subset of the keyboard (arrow navigation). They force developers to make often arbitrary choices about the menu tree (“should Preferences be in Edit or in Tools or in Options?”), and then they force users to make equally arbitrary effort to memorise and navigate that tree."
The Ubuntu HUD is meant to be easy-to-use and supports features like fuzzy matching and can prioritize listings based upon the usage of a given menu item. Canonical is already drawing up plans for a voice-driven HUD to the Ubuntu Unity desktop within the next two years. This is at the same time that Canonical is drafting plans for Ubuntu TV and Ubuntu Smartphones.
Below is a Canonical-provided video that more properly goes over this heads-up display for the Ubuntu Unity desktop. This will be part of Ubuntu 12.04 LTS in April.