The most important piece of information to come out of all of the Tweeting is that "official" journalism is no longer the best source for breaking news of this kind:
I'd add that Mumbai is likely to be viewed in hindsight as the first instance of the paradigmatic shift in crisis coverage: namely, journalists will henceforth no longer be the first to bring us information. Rather, they will be a conduit for the stream of images and video shot by a mix of amateurs and professionals on scene.