Plus, thoughts like "... hmm, but on the other hand, this page is of great value to searchers going by its content, so let's not downrank it quite as much ..." might come in play -- which means there's an editorial* decision of just what is worthwhile content.

*An editor with above average intelligence, above likely to live in California, above likely to be exposed to American media, above likely to understand English etc.?

PS: I don't think it's necessarily really different than before, the editorial part is just more communicated these days.

Yes, "editorial bias" is now a bigger factor.

I think the "something different" is that the editorial part is now much expanded in terms of discretion. Before, they could throw you out, but that was obvious. Even -30 penalities were, in practice, evident. Now, you can go from hypothetically #1 to #5 purely based on something a Google editor does to your page in specific.

Do people buy links in order to improve their Google page rank or to increase the exposure of their sites? My opinion is that people buy links because they need more exposure for their sites. Google must come up with a better way determining the PageRank score, a score that does not rely on back links as is the case at the moment.