There appears to be a major dip every Mid-December to January. There also appears to be a moderate, but much longer, dip starting in May and ending in July. I'

There appears to be a major dip every Mid-December to January. There also appears to be a moderate, but much longer, dip starting in May and ending in July. I'm guessing this speaks more of the average age of users. I expect users with children tend to get less online-time around the summer holidays and especially the Christmas break. I know personally, without children, that I had much less time to access HN around Christmas.