While performing some longhaul flight earlier, I realized that it’s quite quiet during the flight but there were some other pilots around so why not check in on the same frequency (which is active in a large airspace). On there current locations, flight levels, and other important information (like for example severe turbulences) could be shared. For sure a lot people don’t take a look at their devices during cruise, but maybe it would be a nice (not obligatory) function? An example of the airspace’s across Europe is shown below. That way the flights could become more „interactive“ with other people. That frequency could be a Unicom or controlled by a real ATC-controller.
I hope you understand my idea, for any question feel free to ask :-)