Good post. Took me years to find out about "Showdead", and now I too, see dead posts. Some domains return the favor: jwz.org only serves a very interesting image if you're referred from news.ycombinator.com.

I'm also interested in nutcases who post repeated off-topic posts: user pan_cogito (https://news.ycombinator.com/threads?id=pan_cogito) seems to have gone years without realizing all his/her/their posts were dead.