UUCP was pretty much this. E-mail was, in fact, built on top of it; at least Sendmail still supports it. I'm sure you can still find the reasons for the transi

UUCP was pretty much this. E-mail was, in fact, built on top of it; at least Sendmail still supports it. I'm sure you can still find the reasons for the transition to SMTP somewhere. Try, again, Sendmail archives.