I think it works best when people use it like a slide deck--the kind you create and then "send" to someone, as opposed to the kind that is used as a visual aid for a talk or lecture--and carefully organize their tweets so that they have one semi-isolatable (but hopefully rather complete) thought/insight per message. I agree that John Carmack, as evidenced by these tweets, does not seem to know (or care about) how to do that :(... but I've totally seen people do it well; and then, as a "blogging platform", it has the superpower of letting people branch graphs out of your deck, highlighting and commenting on slides while still retaining their context as part of a global discussion.

The (slow) death of blogs and .plan files is probably the greatest net negative Twitter has had on the internet.

Turns out that the people factor is greater than the technological factor.

QA and UX engineers know all about that... :'(