Via The Ohm Project:
Big commercial search engines are not free. They collect as much personal information about you as possible every time you log on, they collect your searches, they analyze them, and they find ways to make money from that information.
The worst is Google. Privacy International (PDF) provided privacy rankings for major search engines and other widely used sites like MySpace and YouTube. At the bottom was Google that PI ranked as absolutely hostile toward its customers’ privacy.
They also recommend Clusty.