He, as one of the leading authorities on the search engine, pronounces it the "new normal" and believes we should pay close attention.
The Google blog post suggests this is an enhancement to search in recognizing your preferred sites from previous searches over 180 days and serving them up more readily.
Now, this isn't truly new. If you'd opted in to this program earlier, Google was delivering it; now it's there for all, opt-in or not, and it's necessary to opt out.
It displays discretely and permits you to shut it off. Sullivan thinks, though, that Google could have done more to publicize and seek permission. More importantly, he feels, we should be closely watching how this change affects our understanding of resources. While he doesn't feel search engine optimization is dead, he notes this is a significant new wrinkle.