What makes you confident that Google doesn't manually adjust weighting and ranking for individual sites? I've always suspected they might -- both increasing and decreasing ranking -- although they won't want this to be well-known for legal and other reasons.

The legal reasons _might_ be enough to keep them from doing it at all, it's true, but I've always suspected they do it anyway.

I mean, we know they do it to penalize certain sites they believe violated their ad rules, right? So we know their systems at least possess the technical ability to manually penalize sites.

But I'm not an expert in this stuff, which is why I start with a question (it wasn't rhetorical!).