Yahoo

AllTheWeb
Search tool owned by Yahoo and using its database, but presenting results differently. Also offers news, picture, video, and audio search.
http://www.alltheweb.com/

Rollyo
Makes it possible for anyone to create their own custom search engines, restricting the index to selected websites. You can also explore other people's searchrolls. It is powered by Yahoo! Search.
http://www.rollyo.com/

Ujiko
Profiling search tool allowing customization of results. The database is supplied by Yahoo! Search.
http://www.ujiko.com/

Wikipedia: Yahoo! Search
Encyclopedia article about Yahoo's search services, including features, history, and technology.
http://en.wikipedia.org/wiki/Yahoo!_Search

Yahoo! Search Blog
A look inside the world of search from the people of Yahoo!
http://www.ysearchblog.com/

Yahoo! Search Blog
A look inside the world of search from the people of Yahoo! [RSS]
http://www.ysearchblog.com/index.xml