As I understand it, the metric divides visits via Google referrals by total visits.

As one example, I typically take short breaks from my intense editing work, about every hour or so. At this time I do a quick check of my favorite sites, including Behind the Black, Watts Up With That, and Drudge. On a typical day, I generate perhaps 10 hits on each site, none of them via Google referrals. So I ad 0 to the numerator and about 10 to the denominator.

I would guess that most people who visit Behind the Black either have it bookmarked, or type it in directly after hearing Mr. Z on the John Batchelor Show. All of these visits register as hits, but not as Google-referred hits.

Drudge gets so many hits per day that it would need probably millions of Google referrals to hit the “normal” rate of 30% by Google referral. A better comparison for Drudge would be MSNBC, Yahoo, or some other news site, which I suspect get most of their visitors in a similar way as Drudge (plus via the advantage of being the default homepage in some instances, such as when getting free wifi in a hotel room or when installing certain search engines).

I think many people have their favorite sites, and visit often without doing a Google search. Many of us visit sites very often, skewing the metric used in this article.

Where Google makes a difference is when people are looking for info on, say, global warming. There must be a better metric for measuring referrals to different sites for particular keywords; that metric may very well show Google to be more biased than shown by the metric used in this paper.

Referencing Drudge;
He absolutely does have huge page-views (like’ 900 million/month) and his monthly unique-visits run around 19 million/month.
https://www.quantcast.com/p-e2qh6t-Out2Ug

Not apologizing for google, but Drudge is a link-farm.
– I only play a search-engine-optimizer-expert, on the Interweb, but one thing about google’s search algorithm(s)– they give weight to both “linked-to” and “linked-from” traffic.
Drudge links to 100’s of items daily, but there are far less reciprocal links leading back to Drudge.
That being said–

I am fairly certain google manipulates everything they do. (and although I have a heavy libertarian bent, it’s a monopoly run by Progressive Statists.)