Yes, the federal government knows what you search for on Google. We know this not just because the Guardian reported it yesterday, but also because of what recently happened to Michele Catalano, a music journalist, and her husband. I'll let her explain (see updates at bottom that contradict Catalano's claim that the search was a result of her Google history):
Most of it was innocent enough. I had researched pressure cookers. My husband was looking for a backpack. And maybe in another time those two things together would have seemed innocuous, but we are in “these times” now.
This was weeks ago. I don’t know what took them so long to get here. Maybe they were waiting for some other devious Google search to show up but “what the hell do I do with quinoa” and “Is A-Rod suspended yet” didn’t fit into the equation so they just moved in based on those older searches.
What happened was this: At about 9:00 am, my husband, who happened to be home yesterday, was sitting in the living room with our two dogs when he heard a couple of cars pull up outside. He looked out the window and saw three black SUVs in front of our house; two at the curb in front and one pulled up behind my husband’s Jeep in the driveway, as if to block him from leaving.
Six gentleman in casual clothes emerged from the vehicles and spread out as they walked toward the house, two toward the backyard on one side, two on the other side, two toward the front door.
A million things went through my husband’s head. None of which were right. He walked outside and the men greeted him by flashing badges. He could see they all had guns holstered in their waistbands.
“Are you [name redacted]?” one asked while glancing at a clipboard. He affirmed that was indeed him, and was asked if they could come in. Sure, he said.
They asked if they could search the house, though it turned out to be just a cursory search. They walked around the living room, studied the books on the shelf (nope, no bomb making books, no Anarchist Cookbook), looked at all our pictures, glanced into our bedroom, pet our dogs. They asked if they could go in my son’s bedroom but when my husband said my son was sleeping in there, they let it be.
After 45 minutes of such nonsense, the search-engine police left. The agents reportedly told Catalano's husband "that they do this about 100 times a week. And that 99 of those visits turn out to be nothing."
Another reason to switch to DuckDuckGo.
Addendum 1: In a Twitter discussion, tech policy reporter (and libertarian) Declan McCullagh suggests that the visit may not have been a result of the couple's Google history. Tweets McCullagh: "Tip from nosy neighbors is likely source, or IP datadump from http://buypressurecookers.com."
Addendum 2: After getting some pushback to her story (which she stands by) Catalano tweeted that she won't be giving any interviews to other media outlets.
Addendum 3: The Guardian has more: "A spokesman for the FBI told to the Guardian on Thursday that its investigators were not involved in the visit, but that 'she was visited by Nassau County police department … They were working in conjunction with Suffolk County police department.'"