Subject: How do web search engines work?

As I understand it, when I use a search engine, I am in essence searching 
the materials of other sites that have been indexed at the location of the 
company housing the search engine. Does this mean that infoseek and 
altavista essentially make huge copies of everything on the web and keep it 
at their site to allow me search all of the web?

how do they do this? do they really get everything and store it there or is 
there some more distributed way that the information is acquired and stored.

Always wanted to know.

-m

Re: How do web search engines work?