Personally I feel HN itself is having this very problem with its community right now. It's not only gotten too big but user "Probablyfiction" nailed it on the head. Too many newcomers destroy the existing culture instead of assimilating into it. The more I read about immigration problems in the USA, Europe (mass influx of Arab immigrants), Africa (mass influx of Chinese immigrants), Isreal (influx of African refugees) the more I notice this same assimilation problem exists in real offline communities as well. [New] Growth (too much too fast) can hurt communities by destroying the original characteristics, culture, and qualities that made them successful in the first place. Time and moderation needs to be given to ensure the new follows the rules of the old when applicable.