What is the main usage of search engine spiders?

[WoodsPainting]

What is the main usage of search engine spiders?

[sulbha]

Hi Friends,
A spider is a program that visits web sites & reads their pages and other information in order to create entries for a search engine index.

The major search engines on the Web all have such a program, which is also known as a "crawler" or a "bot." Spiders are typically programmed to visit sites that have been submitted by their owners as new or updated.

Entire sites or specific pages can be selectively visited and indexed. Spiders are called spiders because they usually visit many sites in parallel at the same time, their "legs" spanning a large area of the "web."

[cathlilly]

From a user point of view there is no need of crawler or indexing. These terms associated with search engines like Google, bing etc., They regularly collects data from websites all over the world and give it to search engines. That way search engines filter those result pages.

[ritesh3592]

A search engine spider, also known as a web crawler, is an Internet bot that crawls websites and stores information for the search engine to index

[sophiawils59]

Search engine spider is a program, sometimes also known as a crawler. Its purpose is to visit every page in a domain and extract all the content present there.

[John-Smith]

Do you mean that what is the use of spiders?

[RH-Calvin]

Search engine spiders are responsible to read through webpage sources to provide information to search engines.