Yahoo Search

and is currently the second largest search engine on the web, after its competitor Google. Originally Yahoo! Search started as a web directory of other websites, organized in a hierarchy, as opposed to a searchable index of pages.

In the late 1990s, Yahoo! evolved into a full-fledged portal with a search interface and, by 2007, a limited version of selection-based search.
Yahoo! Search, originally referred to as Yahoo! provided Search interface, would send queries to a searchable index of pages supplemented with its directory of sites. Originally, none of the actual web crawling and storage/retrieval of data was done by Yahoo! itself.In 2001 the searchable index was powered by Inktomi and later was powered by Google until 2004, when Yahoo! Search became independent. Yahoo! Search major competitors are: Google Search, Live Search and Ask Search.


Search technology acquisition
Seeking to provide its own search engine results, Yahoo! acquired their own search technology.
In 2002, they bought Inktomi, a "behind the scenes" or OEM search engine provider, whose results are shown on other companies' websites and powered Yahoo! in its earlier days.

Initially, even though Yahoo! owned multiple search engines, they didn't use them on the main yahoo.com website, but kept using Google's search engine for its results.
Starting in 2003, Yahoo! Search became its own web crawler-based search engine, with a reinvented crawler called Yahoo! Slurp. Yahoo! Search combined the capabilities of all the search engine companies they had acquired, with its existing research, and put them into a single search engine.The new search engine results were included in all of Yahoo!'s sites that had a web search function. Yahoo! also started to sell the search engine results to other companies, to show on their own web sites.

In addition, Search Assist was added; which provides real-time query suggestions and related concepts as they are typed.
In July 2008, Yahoo! Search announced the introduction of a new service called "Build Your Own Search Service," or BOSS. This service opens the doors for developers to use Yahoo!'s system for indexing information and images and create their own custom search engine.
Yahoo! Search blog & announcements
The team at Yahoo! Search frequently blogs about search announcements, features, updates and enhancements.For some of these supported file-types, Yahoo! Search provides cached links on their search results allowing for viewing of these file-types in standard HTML.
Using the Advanced Search interface or Preferences settings, Yahoo! Search allows the customization of search results and enabling of certain settings such as: SafeSearch, Language Selection, Number of results, Domain restrictions, etc.
For a Basic and starter guide to Yahoo! Search, they also provide a Search Basics tutorial.
In the first week of May 2008, Yahoo! launched a new search mash up called Yahoo! Glue, which is in beta testing. Selection-based search
On June 20, 2007, Yahoo! introduced a selection-based search feature called Yahoo! Shortcuts.

This feature is only active on Yahoo web pages or pages within the Yahoo! Publisher Network. Yahoo! Shortcuts requires the content-owner to modify the underlying HTML of his or her webpage to call out the specific keywords to be enhanced.The technology for context-aware selection-based search on Yahoo pages was first developed by Reiner Kraft.
SearchScan


SearchScan in action.

On May 11, 2008, Yahoo! introduced SearchScan.