alt Hacker NewsIt was more that regular people started joining the internet through just paying for ISPs. Before that, most of the people just joining the internet were students, so there would be a wave of newbies at the start of the university year every September and they would get acclimatised to the culture there during the year. But once it was year-round and many more people it swamped things and the culture shifted or closed itself off.
Exactly. The "September" was an existing phenomenon, but was only limited to a couple of months every year. It became "Eternal" after the masses started finding their way to internet (well, USENET in particular).