To me, the biggest part of this announcement is this:

We’re also introducing a prominent new toggle on the upper right of the results page where you can see what your search results look like without personal content. With a single click, you can see an unpersonalized view of search results.

Google's slowly been making their results more personalized, without having an easy way to opt-out (if you use a Google account). Now that there's this prominent option, I'm less bothered by them adding more personalization by default.