Fredhopper

SDL Fredhopper is more sophisticated than other on-site search tools, recognising the important of on-site search and navigation more broadly in the conversion experience. By tracking analytics, SDL Fredhopper can use this data to become much more intelligent, actually improving the customer experience through eliminating navigational difficulties and presenting the right information at the right time to the right prospects.

http://www.sdl.com/products/fredhopper/