You can burn the Library of Alexandria, and you can make copies of tweets. There's nothing inherent to the art form in the way that copies are stored.
My point is that there is a form of literature that is native to Twitter (or public IM in general), which takes advantage of the specifics of the medium (in particular, unfolding the story at piecemeal bits in real time, and reacting to users comments to tweak the next elements of the story).
The end result may be transcribed to more persistent written storage, but it's not the whole experience (just like reading The Three Musketeers as a book is slightly different to what people waiting for the next chapter in the newspaper would have experienced).
My point is that there is a form of literature that is native to Twitter (or public IM in general), which takes advantage of the specifics of the medium (in particular, unfolding the story at piecemeal bits in real time, and reacting to users comments to tweak the next elements of the story).
The end result may be transcribed to more persistent written storage, but it's not the whole experience (just like reading The Three Musketeers as a book is slightly different to what people waiting for the next chapter in the newspaper would have experienced).