Altavista
This information is sourced from Wikipedia
Unique features that made Altavista the first searchable full-text database on world wide web included:
It also provided the worlds first translation service, Babelfish, that can translate words, phrases or entire Web sites to and from English, Spanish, French, German, Dutch, Portuguese, Italian and Russian.
Yahoo
This information is sourced from Wikipedia
Yahoo! was developed as an online directory for content on the world wide web. In 2002, Yahoo! acquired Inktomi and in 2003, Yahoo! acquired Overture, which owned AlltheWeb and AltaVista. Despite owning its own search engine, Yahoo! initially kept using Google to provide its users with search results on its main website Yahoo.com. In 2004, Yahoo! launched its own search engine based on the combined technologies of its acquisitions utilising a web spider.
This information is sourced from Wikipedia
Google uses a technology called “PageRank”. The number of other websites and webpages that link to a given page is based on the notion that more “relevant” pages are linked to more than others. On this basis, the Google search engine orders its results by how many websites link to each found page. Google (and others) use more than 150 criteria to determine relevancy. The search algorithm “remembers” where it has been and indexes the number of cross-links and relates these into groupings.
Interestingly, PageRank is based on citation analysis developed in the 1950s by Eugene Garfield at the University of Pennsylvania. Google’s founders cite Garfield’s work in their original paper.
Here is another page on the underlying technology of the Google Search engine.
A more recent development has seen Google introduce the Google DIY Search Engine.
Other Useful Links