
Eternal September

Eternal September or the September that never ended is Usenet slang for a period beginning in September 1993, the month that Internet service provider America Online (AOL) began offering Usenet access to its many users, overwhelming the existing culture for online forums.
Before then, Usenet was largely restricted to colleges, universities, and other research institutions. Every September, many incoming students would acquire access to Usenet for the first time, taking time to become accustomed to Usenet's standards of conduct and "netiquette". After a month or so, these new users would either learn to comply with the networks' social norms or tire of using the service.
Whereas the regular September student influx would quickly settle down, the influx of new users from AOL did not end and Usenet's existing culture did not have the capacity to integrate the sheer number of new users. The influx was exacerbated by the aggressive direct mailing campaign by AOL Chief Marketing Officer Jan Brandt, which most notably involved distributing millions of floppy disks and CD-ROMs with free trials of AOL.
Since then the popularity of the Internet has led to a constant stream of new users. Hence, from the point of view of the early Usenet, the influx of new users in September 1993 never ended.
Dave Fischer appears to have coined the term in a January 1994 post to alt.folklore.computers: "It's moot now. September 1993 will go down in net history as the September that never ended."
Legacy.
A tongue-in-cheek program called "sdate" outputs the current date, formatted using the Eternal September calendar (September "X", 1993, with "X" an unbounded counter for days since that epoch). This is not the identically named "sdate", one of the sixty commands that comes with the First Edition of Unix, that is used to set the system clock.
The term is alluded to in Thomas Pynchon's 2013 novel "Bleeding Edge", set largely in dot-com era Silicon Alley, where a "disused techies' saloon" is named "Eternal September".
AOL discontinued its Usenet service on January 25, 2005.