But all of those, "Damn I made a typo or dumb spelling (thx mobile keyboard) and yet it has been replied to or re-tweeted already"... all of that is solved by edit with visible history.
Case 1:
I write "I love cats!" You RT it. I edit it to "I am Al Queda." The FBI visits you.
Case 2:
I write "I am Al Queda." I edit it to "I love cats!" before you see it. You like cats, too, so you RT it. The FBI has a slow feed, so they see that you endorsed my Al Queda membership. They pay you a visit.
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From a systems point of view, when your whole stack is designed around immutability (so you can serve archives of past tweets from append-only CDNs, for example) it may be nigh impossible to add editing.
11
Then the question changes to an age related question. What is the ideal age of a prostitute?
We call that "learning".
Short of [mega star], few tweets see much favoriting/RTing in that window.
It seems that one of the fundamental assumptions is that Tweets are immutable. Changing that could break all kinds of things and would probably their systems significantly more complicated.