DuckDuckGo is actually somewhat more private than Startpage. Startpage is officially a Google partner, so it is not 100% clean; some user identifiable information (specifically, your IP address) is sent to Google.
doesn't mention a specific StartPage/Google partnership (although it does note that search results are from Google), but it does mention a DDG/Yahoo partnership.
And this appears to contradict your IP address statement...
StartPage ~ the world's most private search engine on October 27, 2016 Reply
StartPage is an independent company, separate from Google. We do not share your IP address with Google or with any provider of sponsored search results or ads.
StartPage acts as an intermediary between you and Google. StartPage submits your query to Google anonymously, then returns Google results to you privately. Google never sees you and does not know who made the search request; they only see StartPage.
Since Google never sees your IP address or interacts with your web browser, you do not receive tracking cookies from Google. What’s more, since Google can’t determine your interests based on your past search history, you receive standard search results rather than Google’s “personalized†results.
We never record your visits, your searches, or your IP address, and we do not use tracking cookies. Any ads that appear on StartPage are generated solely from the search term you entered. Ads are not customized for the person entering the search nor do they reflect your prior search or browsing history, since we never access or store that information.
