On the Chaotic Evolution of Email?

TheCarlMau asks: "I'm doing research on the origins of email in the 70's and 80's. I'm particularly interested in how this technology was designed and implemented without any planned trajectory (ie: nobody sat down in 1970 and planned to create email as we know it today in 2006). As very little has been written on the history, I'm wondering if the Slashdot community could provide any insights, stories, or first-hand experiences? It seems to me, as a person who did not experience this 'revolution,' that the offspring of the ARPANET technology was hackish and sometimes chaotic. What do you think on this matter?"