Yes pretty much that.

But only the leader or those with the admin control would be allowed to change it

Yeah I know, the leader organizes it, and you get a message when they create a new folder.

i think it should be one of the alliance rank powers so you can add it to certain ranks like the ability to create a circular message

I agree.

I like this

What, the idea or my plan?

Both,
The idea would really tie in well with the message box that already exists.

Your plan pupairo, neatly shows the concept of the whole thing.

It would be good if the time limit before Circular Messages are deleted is extended as well, this would ensure the idea is not pointless...i.e The messages are organised but deleted soon after.

Plus some circ messages are really handy to keep...sometimes indefinately, It would be good if the different circular message folders also had different times to which the messages are deleted. I.e using some of the folder titles I used earlier:
Announcements - 7 days
General - 3 days
Probe's - 2 days
CR's - 1 day

Nice, but I would put the time that the messages could be deleted at an absolute minimum at 2 days.

Bump, also, here's an updated model of my idea, for clarification. Zorg can add all of the pretty colors and cool effects.

spelled operations wrong and i like the ideas