Interesting (IANAL). So what is the legal distinction, persistence? I read recently that the MLK "I Have a Dream" Speech was copy-written. I assume the difference in persistence comes from the delta between if I go up to the front of an auditorium and read the speech vs if I record that speech to an auditorium and redistribute it. Twitter would be an archive-able public medium is that where its usage as a medium gets moved to illegal?

No, there's no distinction, going up to the front of an auditorium and reading the speech is copyright infringement too. According to the law, that speech is not protected free speech.

(by the way, sorry, nitpick: copywritten → copyrighted)

Yup. I remember when DeCSS hit they had shirts printed up with the code on the back. I know this was a small file the OP sent, but at what point is the medium the moved to a context in which it is free speech? Has twitter reached that point? Are they an immovable third party communications medium?

It's a little different, since the DeCSS code wasn't copyrighted.

Your right to redistribute other people's copyrighted data is severely limited by law. But if something's not copyrighted, and then They say you can't redistribute it, well, then we have something more like DeCSS.