I have to admit, reading the article I went back and forth between being impressed and being slightly freaked out. Best quote from the article that evokes both of those feelings for me: "This is search that truly knows me." Do I really want my Internet search engine to "know me"?
But there's a very thin line between "helpful" and "annoying", especially if there's no easy way to opt-out. And there's no way to know if Google is providing your data to governments or large corporations. Who all knows about me, and how much do they know?
At least the future won't be boring.