It finally happened! After nearly 4 years of development, MPX has been released as part of XI2 in the new X Server 1.7.
The whole thing started when I started my PhD in late 2004. The problem I found was that there was no support for collaboration on a single shared display. All the solutions at the time were hacks at the toolkit or application level. I found that the only way we can get truly collaborative interfaces is by adding it into the windowing system itself. So started hacking on X in late 2005. I went from scratching my head and wondering how some of the stuff could compile (I had never heard of K&R function declarations) to rewriting large parts of the input subsystem and even ended up as release manager. Not in a single day though.
Now we're done. MPX is out, and we have generic low-level support for multiple input devices. You know the whole one keyboard-one mouse paradigm we've had since Doug Engelbart invented the mouse? It's over, you don't have to restrict yourself anymore when writing an app.
Of course, this is a low-level change and when you wake up tomorrow, not a lot will have actually changed. We still need the toolkits to support it, we need apps to pick it up, we need the desktop environments to start thinking about what can be made useful. Nonetheless, basic collaboration features are already there and it can only get better from here.
Let's see what will happen.