The earliest reference for TCP/IP or Internet connectivity from that doc is in 1992. Running locally over finger before that, so I wouldn't consider that an 'internet thing' per se.
I remember using the "finger" command across the Internet back then, late 1992 - early 1993 time frame. You could use it to see if your friends were online or not, based on whether they were logged into the machine. Back then if your email was username@hostname.edu, you probably were logging in (telnetting!) into hostname.edu on a fairly regular basis!
