Well, I for one find the humor to be one of my top reasons for visiting. And I'll go out on a limb and say that I'm in the majority here. I would glaze over (and leave soon thereafter) if all I ever read were dry discourse.
That said, some of the in-jokes get stale with time from overuse. If that is what you were referring to, then I would concur. In my particular case, I often find that someone has already stated my thoughts more eloquently or succinctly than I would have, and given the choice between saying "Ditto!" or making a flippant remark, I'll usually choose the latter.