http://spywarcbzke2e6skl7wjwtmmnrkslue24cld6kfcufjhhwxtceogmuad.onion/articles/firefox.html
For example, from their privacy policy: "When you use our services or view content provided by Google, we automatically collect and store certain information in server logs. This includes: details of how you used our service, such as your search queries.". Then, it was Yahoo, which isn't better: "The Yahoo Search History tool allows you to see what you've searched for in the past. ".