Scary proposition. But stay tuned because without clear data privacy laws, this will not be the the last you've heard of someone suggesting that turning over your search history will get you something you want or need.
That said, I don't think it's quite as black and white as others are suggesting. The specifics in your search history are likely not the issue. It's the overall searches that reveal who we really are. I don't dare to look at my history. Not that it's scary, but because I don't want to be less likely to seek information that I need because of the concern for how it might look at some point in the future when this becomes commonplace. I already do this with facebook. I think about every click and every pause in the scroll.
And if you think this won't become commonplace without clear data privacy laws, think about how many of us (I know there are plenty of individuals.. many of whom comment here frequently.. who don't fit this) have changed our tune about location tracking over the last decade. "I'd never let an app know where I am." was me 10 years ago. 5 years ago: "Does it benefit me enough to give away my location, and/or do I trust the developer enough?" Now: "Is this a super sketchy app or not?"
The IMF floating this idea is what concerns me the most. It will provide legitimacy for exposing us at a very intimate level (and I'm not even talking about pr0n).