Google now tracks voice and mobile search history
Google is constantly updating your Account History page to get more information about what you use their products for. These are used to make suggestions for autocomplete as well as Google Now. But if this isn’t something you’d like them to track, you can opt out through your Account History page. From that page you will be able to pause or even just view your voice search history as well as other information from your smartphone and tablets. You just need to select “Manage history” to delete the stuff you don’t want to be seen.
Source: Google | Via: Lifehacker