Important stuff does have a way of getting lost among what was once relevant posts.
I believe it is in the best interests of the forum and blog to clean out anything no longer relevant.
(I used to work on corporate data control.)
I am not picking on you all, this just makes sense to me.
For example, people who have asked about lawn signs and gotten an answer, maybe clean out your reply? I am not talking about posts that still contain relevant and useful information.
I have done so with some of my forum posts. Others, I would have deleted, have really good comments by other folk. IMHO