There are thousands of search engines available on the internet. Since it’s not possible for all of them to create, maintain and update their own database, most display results from major search engines on their SERP (search engine results page). It is not necessary that all primary and secondary results be provided by a single search engine. Different search engines can provide different results to other engines. Directories can also be used by a third party. The supplier and receiver relationship is demonstrated between many different search engines. These relationships are very important to understand if you want top rankings for your site.
