Your patterns of behavior across multiple sites is not going change whether you're using DDG or Google. And presumably, if you are using TOR, you are not logged

Your patterns of behavior across multiple sites is not going change whether you're using DDG or Google. And presumably, if you are using TOR, you are not logged into Google, using an incognito window, have scripts to block Google Analytics, etc. If the NSA is tracking you across the internet outside of Google's Search Box, you've got bigger problems than Search History. Searching for "Bomb Making 101" is the least of your problems if they see you actually visiting BombMaking.com as well as BombMaterialsShop.com You're postulating a threat model in which anonymized and proxied browsing isn't good enough, because somehow they'll capture all your behavior anyway and then tie it to anonymous search history. My point is, if they can do that, frankly, the fact that they have your search history is the least of your troubles. This appears to be a threat model specifically designed to sell the DDG use case and fight the notion that using Google un-logged in via a privacy browser isn't "good enough". I'm not sure the case can be made that the DDG scenario is marginally better enough to justify worse search results.