So, I just unshared a post from Crosstalk that someone else had shared. I'm sorry, original sharer!
I shouldn't have this power, because I had to click "undo post to Groupthink" when I saw the option the same way other gods feel the need to cause floods and stuff.
I'm a very, very bad god, indeed. Or, can anyone with GT authoring privileges do that? If someone shares a post from another site, can any of us "unshare" it?