My grasp on "the medium is the message" is that it's in part a technological-determinism argument. The message a medium will convey, or perhaps the space of mes

My grasp on "the medium is the message" is that it's in part a technological-determinism argument. The message a medium will convey, or perhaps the space of messages it may end up conveying in practice, is determined by the nature of the medium itself—how it's created, how it's distributed, how it's experienced—resisting attempts to use it for other purposes. That aspect of it, at least, seems useful and to have some truth to it.