DuckDuckGo staff here. Just want to point out that we do not track users - opt in or opt out. We do serve ads that can be disabled (opt-out) but they’re contextual, based on individual search terms rather than any form of tracking.
Thank you for taking the time to set the record straight. I've been a DDG user for a number of years now, and I'm so glad that it exists. Its demonstrated integrity feels exponetially relevant, in contrast with state and corporate behavior these days.
Ah true, if you don't consider logging search queries, and storing device information on improving.duckduckgo.com, and sending all data to your partner Yahoo/Bing, and use affiliate tracking codes.