Here's a thing that happens to me. I see a new thread pop up that looks intriguing - say, the"cold junk" or "alternative term for quiver" thread this week. But by the time I get around actually to opening it, I see with dismay that there are hundreds of posts already, and just skip it. Basically I'm too lazy or busy to want to invest the time to get up to speed. Depending on my interest level in the nominal topic, this usually happens somewhere between 25 and 75 posts on a new thread.