[So they now throw some randomisation into the mix for an as yet unknown period of time. Moving on and buidling afresh is a smart move - revisit in a years time.]
Again, this isn't entirely new. "So they now" is a misperception.
Patent filed in Jan 2010. Which means likely working on it on 09. Furthermore, there are elements of a transition rank as far back as Dec 2003 with the historic ranking factors patents.
This is why there is context required for this story. Sure, the terminology has changed, (like the obvious KW stuffing of the term [spammer] in this one...LOL) but there is still an evolution and we shouldn't start looking for something new. More so, we should compare what we know and have learned over the years with this being a glimpse into causation in our daily activities.
Really want to get ahead? Stop reading patents and start reading papers. Research papers from Google or even those of major Uni (Stanford comes to mid). Why? Because patents are the past. Papers are the future. This is where the ideas and people begin the genesis for the future of search.
When one reads a patent, SOP is to research the people that worked on it. What department(s) have they worked in? Where did they go to Uni? What papers did they write at UNI? One seeks to get a deeper mindset into the patent itself. Those writing papers today, could be a Google employee tomorrow.