Ah, JSexton, if only it were that simple.  No, B1FF@BIT.NET (or was it B1FF@psuvm.psu.edu?) is far, far older than AOL’s descent onto Usenet.  Witness the Jargon File entry.  And the AOL invasion itself was merely the tail end of the Usenet invasion.
Actually, more like the Humvee that broke the camel’s back.
Once upon a time, in an Interweb far, far away…
Usenet (“news”) started out as a message board protocol between multiple universities.  It slowly grew and as the students who used it propagated into businesses and government agencies, so did the news spool propagate.  Over time it slowly changed, but it never fully outgrew its origin, and from its origins did it exibit a particular property.  And that property was called…
September.
Yes, every September, the universities would get a new influx of students, many of whom would eventually wind up finding Usenet and would blunder into many newsgroups, such as soc.motss or alt.fan.cecil-adams, unaware of the standards of behavior (“netiquette”) of those groups.  Everything would sort itself out in a couple of weeks, or at most a month, but it was a known occurance, with its own memes (“Is it September already?” – a common reply to a post that made little or no sense).
And in September of 1993, as in all other years, the influx occurred, and everyone tolerated (well, maybe not in alt.flame) the off-topic posts and the obnoxious signatures (except in alt.fan.warlord) and the people unable to type without using the caps lock key.  Those exhibiting such behavior were referred to such resources as Emily Postnews’ guide to netiquette, or to the Internet FTP W@R3Z site, 127.0.0.1, as needed.
But then, right as such behavior was about to tail off, Boom! GEnie gave its members access to Usenet.  And people complained that September was lasting overlong.  But things began to get better until Boom! Compu$erve gave its users access to Usenet.  And the netizens languished in the extended September, holding tight to the belief that this, too, shall pass.  And then, only then, did AOL, driven by its competitors to open the floodgates and give its users access to the Internet.
Thus began The September that Never Ended.
Wikipedia gets it mostly right:  http://en.wikipedia.org/wiki/Eternal_September