Before I RTFA, I was wondering if this would be about trying to find a way to include Wayback Machine results in search. Searching the Wayback Machine is always such a nightmare, and wouldn't it be nice if your search turned up that long-dead 1997 web page that has the exact answer for what you're looking for...
(minor use case I had recently was I was trying to find old Japanese blogs for Tamagotchis, which I gather there were a ton of in the 90s but almost none survive today - imagine if I could get those instead of the 1,000,000 sites just trying to sell them to me)
What a pleasant website theme for reading.
It's a real edge case, but someone could conceivably let their own domain expire and then register it anew and restore their website. It will be impossible to tell this apart from an SEO buying and restoring a website to use for link juice.
Yeah there's no shortage of caveats in this space. One could conceivably compare the outgoing links (being a search engine and all and having historical crawl data to compare against), but my hunch the cost of distinguishing between these two cases is going to be way out of proportion when compared to the benefit.
The DNS records would be completely revamped, or removed in that case.
Kagi has this feature, “Blast From The Past” https://blog.kagi.com/kagi-features#:~:text=Interesting%20fi...
They're likely only serving previously accessible domains already in their index as wayback machine links, which is neat, but doesn't really solve the problem of indexing the wayback machine in a broader sense.
Would be a very nice feature to have indeed, though the data is a bit too inaccessible to index as far as I can tell (even though I've not given it any serious effort, so maybe it is?)