This algorithm change could come across as more editorial and less empirical. It's publicized as highly targeted ("slightly over 2% of queries"), responding to

This algorithm change could come across as more editorial and less empirical. It's publicized as highly targeted ("slightly over 2% of queries"), responding to small tech discussion (Atwood, SO, HN, quality launch meeting), and seemingly rolled out in a short period of time. The media could easily boil this down to "a small number people felt sites they liked were under-ranked, so Google moved them up a week later." I mention this because Google often talks publicly about being entirely algorithmic, and elements of this narrative feel human.