Search engine types

[webustaad]

Dear webmasters!

We know that there are 5 types of search engines.

1) True search engines (spider engines)
2) Directories
3) Hybrid search engines
4) Meta search engines
5) Pay per click

What types of engines are these?

[google.com...]
[yahoo.com...]

[Imaster]

Google is a crawler based search engine which uses directory results from Dmoz to improve its relevancy.

Yahoo is a web portal which is a directory + a search engine powered by Google.

[webustaad]

This means that yahoo and Google are hybrid search engines (combination of a directory and crawler based engine)

Thanks for your reply.

[Imaster]

Yes, they are: http://searchenginewatch.com/facts/article.php/2168031

[John_Caius]

Google doesn't present a combination of crawl and directory results - it's just that sites listed in dmoz get ranking points from dmoz.org itself and from directory.google.com, both of which are very high PR sites at root. The search results from Google are entirely crawl-derived. We have had this discussion many times and it is clear that Google does not give sites listed in dmoz any kind of boost.

msg #8 - [webmasterworld.com...]

[Marcia]

Google is a crawler engine that also happens to have a directory. Yahoo is a portal that runs a directory and uses the data from a third party search engine, currently Google, to provide their search results.

Google is a search engine, not a directory.
Yahoo is not a search engine. The Yahoo Directory is a directory, not a search engine.