I did mention AOL, as part of the "Eternal September" of Usenet (so tangentially, but still acknowledging it was there) but yeah, I did skip over some of the others. CompuSERVE was something I thought was really cool at the time, but there was no way my parents would pay those hourly charges for me...
I fondly remember my first few experiences after the family PC got it first modem and computing has never been the same since.
Surprisingly the author skipped over CompuSERVE, Prodigy, and AOL, all of which had very active messaging forums and early chat systems.