Google used to have something on their front page to the tune of "What other people are searching right now!" To sort of add a lively "Here's what's trending!"

Google used to have something on their front page to the tune of "What other people are searching right now!" To sort of add a lively "Here's what's trending!" kinda thing They pulled that feature really fast when it made users acutely aware that their searches were not at all private. So... Likely this reason.