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".