In 1993, the online service America Online began offering Usenet access to its tens of thousands, and later millions, of users. To many "old-timers", these "AOLers" were far less prepared to learn netiquette than university freshmen. This was in part because AOL took few pains to educate its users about Usenet customs, or explain to them that these new-found forums were not simply another piece of AOL's service. But it was also a result of the much larger scale of growth. Whereas the regular September freshman influx would soon settle down, the sheer number of new users now threatened to overwhelm the existing Usenet culture's capacity to inculcate its social norms.
Since that time, the dramatic rise in the popularity of the Internet has brought a constant stream of new users—in some people's view, drowning out the old Usenet entirely. Thus, from the point of view of the pre-1993 Usenet user, the regular "September" influx of new users never ended.
It's moot now. September 1993 will go down in net.history as the September that never ended.
The gag is at times extended—for instance, the notional future date at which Usenet discourse will become sensible, mature, and educated has been called "October 1, 1993". An attempt to hurry the arrival of that date is being made by the proponents of Usenet II.
On September 16, 2008 Comcast discontinued newsgroup access, previously provided to all its high speed customers. This led some commentators to claim that perhaps September is finally over. Others though look at the removal of service from almost all ISPs as a whole to be the end of Usenet altogether a result of influence by politicians who have stated that the service was a bastion of child porn that must be stopped.
Other ISP's have canned Binary groups (Telus in Canada) and some have disabled USENET (Rogers in Canada) altogether.