What is algorithm in relation to search engines, how does it work?

What is algorithm in relation to search engines and how does it work?

The gross oversimplification of a search engine is this:
They index the web by following links between sites, starting from highly interlinked websites, and then crawling all subsequent links from there. Then, the search engine indexes the contents of the pages they have found. After that, they score each document using a proprietary process and cache the results.

Then when you query a search engine, due to the precalculation of all these factors, they return a set of results that are the best match to your query, given what you typed into the search box.

For the funadvice search engine, we use a ruby on rails port of lucene referred to as Ferret, as far as I'm aware.

Hope this helps.
Best,

thedude