I have two stories.
I had a technical question about something and the author of the paper was in Japan. I could call or send a letter. Calling was difficult, expensive and awkward. Mail would take weeks. Then I noticed there was an email attached to the paper and on a whim, sent and email. I was stunned and bewildered to get an answer to my question less than twenty minutes later. From Japan! I just remember the feeling of staring at the reply and not really comprehending how it could be there.
Also, people started mailing lists. It was quite exciting because now there were places you could hear about other people working on the same problems. One day I got an email about a new mailing list and promptly signed up. A few minutes later I started getting tens and then hundreds of email messages about people signing up - "Yes add me to the list". Then a few minutes later, thousands of messages about "Remove me from the list". People did not understand the difference between "reply" and "reply all" or maybe the mailing list software had a bug. But it was hilarious.