Usenet, a major discussion system of the early Internet and precursor to Internet forums, was a place of civility and professionalism — except in September, when first-year university students gained access to the Internet and Usenet through their university campuses and wreaked havoc for a few weeks before learning online etiquette. In 1993, Internet service providers made access to Usenet much easier. What followed was a continuous deluge of new users the likes of which Usenet had never seen before. Thus began Eternal September, the September that never ended. As usual, more info at Wikipedia.