An answer to this question on Reddit.

This was twenty years ago, I was seven. At school, the teacher asked whether any of us knew someone with an email address, I was the only kid in class who did. The next day I brought my dad’s email address on a piece of paper, and the whole class sat around me as I wrote the silliest email, saying something like ‘Hi dad, I’m writing you now’. My dad replied a day after, again the whole class sat around the computer as we opened this new ‘digital post’. That felt like the future, yeah.