How do major search engines create their directories?

[gurweb]

I understand that major search engines spider to find sites, but what I don't understand is how search engines can find new sites? What criteria is used to find new sites by search engines? How did google and yahoo create their database when they first just started from scratch? Did they spider through links to find websites or did they depend on manually entering all the websites?

Please let me know =)

[creative craig]

Welcome to webmasterworld, gurweb :)

Google finds new sites by following links, to actualy find the site there is no set criteria, once the site is spiderd there is then a criteria that is looked at to judge where the site should rank in the results page.

This page shows how a search engine works and what happens when a spider finds a page:

[webmasterworld.com...]

And this page shows the history of Google how it started and might answer the your questions a little more:

[www-db.stanford.edu...]

Craig