Google could do this too they just chose not to- all that tracking is to power their ad networks so that ads can follow you around the Internet using your search history and other information they have on you.

That’s how we make money and it doesn't involve tracking because it is based on the keyword and not the person. When you search ‘car’ we can show you a car ad without knowing anything about you. In fact, it’s a myth that you need to track people to make money in web search. On Google, your searches are tracked, mined, and packaged up into a data profile for advertisers to follow you around the Internet through those intrusive and annoying ever-present banner ads, using Google’s massive ad networks, embedded across millions of sites and apps. All of that personal information should be private, but on Google it’s not. You share your most intimate secrets with your search engine without even thinking: medical, financial and personal issues, along with all the day to day things that make you, well, you. Why Should I Use DuckDuckGo Instead of Google? Filed under DuckDuckGo Q&A

Gogoduck news