If the US Justice Department gets its way, your past searching data (also called attention data) on Google may be up for grabs to the FBI and other government agencies! No matter what you may have searched for in the past, those keywords, and possibly even some form of identification to your PC, could end up on someone's desk.
While you may have nothing to worry about even if this were to occur, who wants this kind of privacy invasion? The goal is for the US to limit children access to pornography sites. One can certainly not argue against their goal, but the means to do it is the problem. Although I have been steadily becoming more skeptical about Google's motives (much like Microsoft around 1997), I am happy to hear they will be fighting to hold on to this data.
Don't forget, there are plenty of other search engines out there.