What Search Engines Really Provide a "Private" Browsing Experience?

Thanks PO3 Steven Sherrill the only search capabilities I remember that were relatively secure were on classified networks and yet they were monitored by system administrators back in the days when I supported ... in the Pentagon.

None. The key to a successful search engine is not just a huge collection of links to data, but also the fact that it ranks results according to popularity. How can it rank them with recording search histories? How can it provide personalized responses without keeping a record of your search history?