The biggest problem here is not the support cost, but that offering this kind of information gives people insight into how the algorithm works so they can better game it.
In search, email, etc there's continual competition between people trying to trick the span detection algorithm and people trying to extend the algorithm to counter them. Secrecy is a critical tool on both sides of this fight. Force transparency on the algorithm maintainers and it's output will get much worse.
Keeping the algorithm secret has downsides, but is worth it (for society at large) on balance.
(Disclosure: I work for Google, on unrelated things, and don't know anything Google-specific here.)
That's not the level of detail I'm asking for. I'm not talking about publishing the algorithm.
But if there is a dramatic change in ranking or my site is removed entirely, it should be possible to ask Google to investigate (possibly automated) and tell me if something out of the ordinary has happened.
Secrecy shouldn't mean to hide simple mistakes on either side. That makes search results worse not better, as it was clearly the case with protonmail.com
In search, email, etc there's continual competition between people trying to trick the span detection algorithm and people trying to extend the algorithm to counter them. Secrecy is a critical tool on both sides of this fight. Force transparency on the algorithm maintainers and it's output will get much worse.
Keeping the algorithm secret has downsides, but is worth it (for society at large) on balance.
(Disclosure: I work for Google, on unrelated things, and don't know anything Google-specific here.)