But that number has no way of inspecting it to know what it actually means. Is it including prefix searches? Suffix? Whole word only? Possible misspellings? Acronyms? Translations?

I get that it can be somewhat directional, but I question that anyone is getting meaningful data out of it. :(

Also, some pages are mirrored all over the internet.

You've just opened a can of worms. It raises a very interesting question: when asking something like

> if I want to know the most commonly used spelling between two options

do those mirrors count as "use" of the word? Or does "use" refer only to the original writer?

If a neologism is written once and read by millions, it carries more weight than one read by only a few people. Perhaps the same goes for spelling variants: the more people see it, the more people agree it's the typical spelling. Lots of mirroring could be a decent proxy for lots of readership.

You can in some cases compare different keywords to each other.

The number is not _the_ information. It's just _some_ information. When I search the web I want the content, and very very rarely care about the actual number of results. So yeah, showing a search result count they can't actually serve is dishonest and gives a false sense of reality.

No, in context of what I said (when the number is what you're looking at) the number is the information. If the content is what you care about, the number being 2 million or 5 million is meaningless because you'll never get through all the content.