Eternal September or the September that never ended is Usenet slang for a period beginning around 1993 when Internet service providers began offering Usenet access to many new users. The flood of new users overwhelmed the existing culture for online forums and the ability to enforce existing norms. AOL followed with their Usenet gateway service in March 1994, leading to a constant stream of new users. Hence, from the early Usenet point of view, the influx of new users in September 1993 never ended.
As part of the eternal September myself, we didn’t just use AOL disks as coasters, we used them for awesome pranks like filling eachother’s cars to the brim with them. It was truly astonishing how many of those disks were around.