With Wayland will we be able to: Have multiple seperate wayland sessions on the same computer, as many as one wishes, with many of them being headless, accessible if the user wishes through a remote desktop solution such as VNC? Will be able to use a command line switch or environment variable to determine which wayland session an application should be started in on a per application basis? Does the wayland environment provide information on what areas of the screen are visible to apps, similar to Expose events? This could also be done with a pointer to shared memory data structure that contains a list of exposed areas. If this is not provided, I would be concerned applications will waste time drawing areas of their window that are not visible. I previously asked if one can run an rootless and an session in-window X Server as a wayland client, to a wayland session, so x applications can be displayed on a wayland display, and if one can display a wayland session and even individual wayland apps onto an X server. I think that these are very important features. Being able to display individual wayland apps to an X server selectable at runtime, is a highly desirable feature, this would solve the need for headless remote desktop sessions, since I could display wayland apps to Xvfb (headless) and use x11vnc with Xvfb. These features will be necessary. The fact is, toolkits and applications cannot be trusted to provide runtime switchable display targets between wayland and X11. We've had experience with similar situations that shows that application developers will neglect this. Back when XRender extension was implemented, a large number of X applications ended up not supporting a fallback for servers that did not support XRender, despite the assurances that they would. This led to X applications not working at all on servers that did not support X render. The situation will be similar this time around. A number of applications will neglect support for display to x11. Users should not be forced to give up their x11 environment, many of us have specially tuned X window manager configurations, and the way to assure that this will not happen is to gaurantee that individual wayland only applications can be displayed to an X server through some facility for this purpose, allowing us to run wayland applications inside our X sessions with our preferred X window manager.