>Some investigation seemed to suggest they were hard excluding any page which hadn't changed in ~5 years. I had another hypothesis: that they exclude pages whi

>Some investigation seemed to suggest they were hard excluding any page which hadn't changed in ~5 years. I had another hypothesis: that they exclude pages which have no backlinks from other websites, and at the same time are hard to reach from front page of the website they are on. It seems old unpopular mailing lists posts and forum posts are exactly like that.