With regards to Eternal September, you're exactly right. Prior to that AOL invasion you had relatively small bursts of new people joining with no predetermined

With regards to Eternal September, you're exactly right. Prior to that AOL invasion you had relatively small bursts of new people joining with no predetermined cultural expectations who had to assimilate into an existing culture. When AOL hit usenet you had a massive number of people with their own established cultural expectations due to the walled and managed AOL garden colliding with the existing Internet culture, and the Internet culture was overwhelmed. Prior to Eternal September the primary conception of the Internet by those on it was that it was a tool. After Eternal September the primary conception was that it was a channel for consumption and entertainment.