[thaumasiotes]

That's how it works. It's exactly what he says it is.

[thrdbndndn]

I still don't get how it is done.

1. How do you track which day had a black bar? By web.archive?

2. How do you associate the day to a specific post? I guess this should be fairly easy, albeit kinda manual.

[mikequinlan]

The page itself says

This list was compiled using a simple Python script that recursively requested HN's Algolia search API for posts containing "has died". For each relevant hit, I pulled in snapshots from the Wayback Machine to see if the HTML document contained the black bar element at the end of the day the post was created. It's possible there are names missing.