[derefr]

> I'm wondering the same thing.

Well, if you really want to know, you could try taking the HTTP responses for the page you expect to be highly ranked, and the page that's actually highly-ranked, and applying various common ranking heuristics to them, to figure out what the result-ranking algorithm is actually doing.

For any search engine who hasn't had a bunch of competitive pressure forcing them to improve, the ranking algorithm is very likely something incredibly simple and standard — e.g. tf-idf across the whole HTTP-result corpus.

So I'd guess that the results you tend to see in your tests, are because one of those "standard" algorithms ends up doing something dumb for the ranking pairs you care about.