E-mail for me back then would be doing a nightly pack of all messages in my BBS, sending that off via dial-up for a couple of hours to a central server in the region. They in turn pack all local messages and upload it to the national server which makes an exchange further up the line for international exchange. Think FIDONet.
Responses were typically a 24-48hr time period, assuming folks respond quickly. Back then, that was quick!
These days, people at work freak out if i don't respond within a few minutes. Darn whippersnappers.
p.s. I ran that BBS on a massive 20mb "Plus+" drive that was roughly 18" long and plugged into an IDE slot. Ah, fun times. Wish i kept that piece of antique hardware, haven't seen anything like it since. On slow days, some folks would call me to swap out the disc of free/shareware that i had on my single cd drive. Eventually i just manually swapped them on a weekly basis to keep content "fresh".