In our world of customized online services, responsible use of data is critical to establishing and maintaining user trust. [...] We know that our users expect relevant and compelling content and advertising when they visit Yahoo!, but they also want assurances that we are focused on protecting their privacy.

Anne Toth, Vice President of Policy and Head of Privacy.

It is mandatory that such companies respect our right to browse the internet as anonymous as possible, while using their services. There are better (but definitely more expensive) methods out there to make search results better.