Eternal September

Before the Internet became mainstream in the mid-1990s, Usenet was largely restricted to colleges and universities, meaning that September (the start of the academic year) represented the largest annual influx of new users. Around 1993, commercial ISPs began offering Usenet access to their userbases, leading to a large amount of new posters with little idea of netiquette joining year-round. From the perspective of experienced Usenet users, the influx of new users in September 1993 never ended.

Eternal September

1. (Internet slang, historical) A period beginning around 1993, in which large amounts of new users were joining Usenet.

   Synonyms: Endless September, September that never ended

   • 2015 September 30, Jason Koebler, “It's September, Forever”, in Vice‎:

     "September 1993 will go down in net history as the September that never ended," Dave Fischer wrote on the world's most popular social network at the time. That post spawned the idea of the "Eternal September," a phenomenon that happens when an internet community is forced to deal with a neverending influx of new people.