I've gotten into a habit of instinctively searching for queries in multiple major search engines as I've often found that many useful results are found by one but not another. Most of the time, notable differences seem to be in NLP or 'Oh, I know what you're looking for!' algorithms or are the result of DMCA or other requests, but I've noticed a few situations like this where results differ or seem special-cased, sometimes amusingly, for mysterious reasons (edit: another comment points out possible copyright issues with Wikivoyage).

Here are a couple cases where I archived results pages from Bing, Google, and Yandex with the Wayback Machine and archive.is.

A particularly puzzling case as to why the result might be filtered: one particular Wikipedia page. Searching by its title, using the queries:

  victorian erotica wikipedia

or

  "victorian erotica" site:en.wikipedia.org

Bing refuses to present the page, while Google and Yandex offer it with no qualms. Interestingly, when I discovered this, the article's talk page was the first result in Bing, but now even that no longer appears.

Another query, where the issue is likely that it borders on one of a diverse variety of sensitive and/or politically controversial topics where results sometimes seem deliberately tuned in one index or another (in my anecdata: mostly by Google), is the title of one of the hoax papers submitted in the grievance studies affair, which appears verbatim in many pages about it:

  my struggle to dismantle my whiteness a critical race examination of whiteness from within whiteness

Bing and Yandex exhibit expected behavior. Google, however (which is usually the best at determining the subject of a query consisting of an out-of-context quote) seems to only focus on a small fraction of keywords and finds no results that are remotely related to the grievance studies affair itself.

I've seen discussions about the decreasing relevancy of search results in general where some have suggested that some sort of central repository be started for archiving interesting search results. I wonder if there have been any efforts toward such a project?

Note: when archiving search pages, I stripped all unnecessary parameters from the URLs. For example,

https://web.archive.org/web/0/https://www.google.com/search?...