How Does a Search Engine Work?

The Basic Inner Workings of Search Engines

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Search engines are complicated entities. Here is a basic breakdown of how search engines work to bring you the results you're looking for.

What is a search engine?

Basically, a search engine is a software program that searches for sites based on the words that you designate as search terms. Search engines look through their own databases of information in order to find what it is that you are looking for.

Are Search Engines and Directories The Same Thing?

Search engines and Web directories are not the same thing; although the term "search engine" often is used interchangeably. Search engines automatically create web site listings by using spiders that "crawl" web pages, index their information, and optimally follows that site's links to other pages. Spiders return to already-crawled sites on a pretty regular basis in order to check for updates or changes, and everything that these spiders find goes into the search engine database.

A spider, also known as a robot or a crawler, is actually just a program that follows, or "crawls", links throughout the Internet, grabbing content from sites and adding it to search engine indexes.

Spiders only can follow links from one page to another and from one site to another. That is the primary reason why links to your site (inbound links) are so important.

Links to your website from other websites will give the search engine spiders more "food" to chew on. The more times they find links to your site, the more times they will stop by and visit. Google especially relies on its spiders to create their vast index of listings.

Spiders find Web pages by following links from other Web pages, but users can also submit web pages directly to a search engine or directory and request a visit by their spiders.

In fact, it's a good idea to manually submit your site to a human-edited directory such as Yahoo, and usually spiders from other search engines (such as Google) will find it and add it to their database. It can be useful to submit your URL straight to the various search engines as well; but spider-based engines will usually pick up your site regardless of whether or not you've submitted it to a search engine. Much more about search engine submission can be found in this article titled Free Search Engine Submission: Six Places You Can Submit Your Site For Free. It should be noted that most sites are picked up automatically upon publishing by search engine spiders, but manual submission is still practiced. 

How Do Search Engines Process Searches? 

Please note: search engines are not simple. They include incredibly detailed processes and methodologies, and are updated all the time. This is a bare bones look at how search engines work to retrieve your search results. All search engines go by this basic process when conducting search processes, but because there are differences in search engines, there are bound to be different results depending on which engine you use.

  1. The searcher types a query into a search engine.
  1. Search engine software quickly sorts through literally millions of pages in its database to find matches to this query.
  2. The search engine's results are ranked in order of relevancy.

Examples of Search Engines

There are a TON of great search engines out there for you to choose from. Whatever your search need might be, you'll find a search engine to meet it.

  • 100 Search Engines in 100 Days: All-purpose search engines, visual search engines, people search engines...you'll find all these and more in this list of search engines, a comprehensive guide to the best search engines on the Web.
  • How to Pick a Search Engine: Pick the best search engine for your searching needs with Search Engines 101, a great way to explore more of your search topic, try a new search engine, and search more of the Web.

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