@herrabre First of all I want to make sure we're not misunderstanding each other. When you wrote postpone, in the sense of marketing stuff for people in different timezones, I assumed automatic publication. If (for the drama thing) you don't mean postpone-publish but rather "drafting" (think blogging), then you can ignore the rest of this post because drafting is something I fully support.
Well if you want to comment something later, why not just comment it later? If you, say, write something in the heat of a moment or something that may be considered inappropriate etc, then I don't see why - if you really want to publish something later - you simply publish it later.
I expect such a feature would just let you forget things that were postponed and then when they're published it still caused drama (unless you postpone the postponement...).
I humbly believe this is yet another technical solution to a social problem that will not really solve anything.