I think should be something global, not local to an application,
because this wouldn't solve the problem of discoverability of the
click on the track, and of all the applications that doesn't have an
edit menu.
+1
Furthermore, I'm just wondering how many people have copied something to paste it later, and then accidentally copied something else, causing the intended information to be lost?
Also, I am really annoyed when I copy something from one application, close it, and then try to paste it somewhere else. This is ridiculous! Why is copy/paste application centric?
For these reasons, I think a simple clipboard indicator would be a good step forward:
It would store data independently from applications.
It would store recent copied data, so you could copy two things, and paste them both.
It would be a menu that listed the copied data, and would paste the data when the corresponding menu item is clicked.
It would allow global indication of whether there is something ready to be pasted:
A transparent state means no data
A green state means recently copied data (maybe slowly fade over time)
A sold white state means old data.
Regarding the original thread, with such an indicator, a click of the track would cause the clipboard indicator to become a solid green, and thus the user would know something was copied. A simple click (or even menu scrub) over to the clipboard indicator would show exactly what was copied, and voila, the user has discovered the functionality.