Right now Hacker News combats eternal September systematically through hell banning and a karma system. The karma system is actually set up in a way that tries

Right now Hacker News combats eternal September systematically through hell banning and a karma system. The karma system is actually set up in a way that tries to select for the best possible material. A user's karma and their post's karma are both factored into how far up the page a post will be displayed. This leads to new users being exposed to the hacker news culture more frequently. Post feedback is also set up in this way, because older users are the only ones capable of downvoting. -- Eternal September is named the way it is because in the past online communities only had to deal with influx when students got to college, but now they have to deal with a constant influx. Given this, it seems obvious to me how you go about countering Eternal September: remove the eternal. This could be done in a few ways, but the core idea is having a period in which registration has a barrier for most of the year and periods in which the barrier is removed for the sake of growth. I don't think PG would want to do that though, since it might have negatively affect the number and quality of the applications YCombinator receives. Other sites also avoid this option out of a desire for users. The incentive structure makes my obvious solution fairly useless.