The network message can in effect be in the present
Writing, chirographic or typed, on the other hand, comes out of the past. Even if you write a memo to yourself, when you refer to it, it’s a memo which you wrote a few minutes ago, or maybe two weeks ago. But on a computer network, the recipient can receive what is communicated with no such interval. Although it is not exactly the same as oral communication, the network message from one person to another or others is very rapid and can in effect be in the present. Computerized communication can thus suggest the immediate experience of direct sound. I believe that is why computerized verbalization has been assimilated to secondary ‘orality,’ even when it comes not in oral-aural format but through the eye, and thus is not directly oral at all.
John Walter, “Tertiary Orality, Secondary Literacy, and Residual Orality”