Notable how this is only possible because the website is a good "web citizen." It has urls that maintain their state over a decade. They contain a whole conversation. You don't have to log in to see anything. The value of old proper websites increases with our ability to process them.
It's a shame that maintaining the web is so hard that only a few websites are "good citizens". I wish the web was a -bit- way more like git. It should be easier to crawl the web and serve it.
Say, you browse and get things cached and shared, but only your "local bookmarks" persist. I guess it's like pinning in IPFS.