What Is a Search Engine Spider?
When most people think of spiders, they probably picture those 8-legged insects that spin webs and eat bugs. But in the world of the Internet, the term “spiders” refers to something else entirely.
Whether or not you know it, each time you perform a search on the World Wide Web, your results are found by search-engine spiders.
So what exactly is a search engine spider?
As the Internet began to grow in the early 1990s, web programmers began to realize it would soon be impossible to search all of the pages on the web to find information.
To solve this problem, they began to develop programs that, through links, would quickly search all of the available web pages. Relying upon the fact that every page on the Internet links to another page, the program would quickly search all web pages and check each the links on those pages.
With this program, a greater number of more accurate results would be returned to the user. Although it took programmers a while to get this program to where it is today, the idea marked the birth of the search-engine spider.
As search-engine spiders search the web for information, they are often referred to as search-engine robots or crawlers. Because they can find information much faster than people (it would actually be impossible for humans to pull data as quickly as the spiders), results appear instantaneously.
When you call up a search engine and type something into the search box, the second you hit “Enter,” those spiders start scouring the web. In less than a second, they provide you with the most relevant and updated pages they were able to find—and even rank them in order of relevance.
So how do the spiders determine what information is relevant to your search? First and foremost, they quickly read millions of web pages (think of them as extremely talented speed readers), looking for the same word or phrase you typed into the search box.
Once the spider identifies pages containing that word or phrase, it then searches for links within those pages. Why links? Simply put, sites that link to other sites tend to be more trustworthy. Additionally, those links help the spider determine the topic of any given web page.
For search-engine spiders to find information on the web, the content of a site must be search-friendly. In other words, the information on any particular page must link to other relevant pages, and be written in such a way that a search-engine spider can easily read it.
Unfortunately, creating a website that meets these requirements is not that easy. For that reason, many companies now specialize in website design and search-engine marketing.
Search-engine spiders don’t actually search the web as it exists at that given moment. Rather, the information they are searching is actually a slightly outdated index of all of the sites on the web.
Because search engines only update their results every few days, the information the spiders find is not always the most up-to-date–but it’s pretty close!