Having following this thread over the past two days and doing many searches on google, I have to say something about quality of content. It appears to me that the new metrics regard the detailed, long and articles are good. I don't think so. Quality can not measured by the words of articles. As a scientist, I know the short "Nature Review" is the best review of all and even more useful than original scientific research papers.
With more and more people use smart phones browsing Internet, the long articles become less useful. If not do it right, google might lost the market share to other search engines, such as Bing.
I noticed the the small to medium sites, with niche content and lots of ads were hit hardest.