Exactly! If people can't be bothered to proof-read a mere 140 characters before clicking the Tweet button, then they don't deserve an edit facility. Get it right the first time, or delete it and repost. Sadly, though, reading what one has typed before clicking a button is a rare thing these days. Too many people seem not to have figured out that they are judged by the quality of what they write. Bad writing allows me to infer that you're an uneducated dimwit. At least it's a good way of identifying rubbish that doesn't need to be read to its conclusion (admittedly, not really a problem for Twitter, but it is in other places).