Some people who use the internet still think, wrongly, that real people visit each website and then add it to the search engine's database. What if these things were true? There are billions of websites on the internet, and most of them have new content. It would take thousands of people to do what search engine spiders and robots do, and even then they wouldn't be as quick or thorough.
Search engine spiders and robots are pieces of code or software that only do one thing: look for content on the internet and on every single web page. These tools make a big difference in how well search engines work.
Search engine spiders and robots go to websites and get the information they need to figure out what the website is about and what it has on it. This information is then added to the search engine's index. Search engine spiders and robots follow links from one website to another to get the information they need. They do this over and over again until they have all the information they need. The ultimate goal of search engine spiders and robots is to build a big, useful database that can give visitors the best results for their searches.
But how do spiders and robots in search engines actually work?
When a web page is sent to a search engine to be added, the whole process starts. The URL you gave is added to the list of sites that the search engine spider will visit. Submissions aren't required, though, because most spiders can find the content of a web page if other sites link to it. This is why it's a good idea to build links with other sites that go both ways. By making your site more popular with links and getting links from other sites that are about the same things as your site.
When the search engine spider robot visits a website, it looks for a file called "robots.txt" to see if it already exists. The file tells the robot which parts of the site it can't look at, like some directories that search engines don't need. All search engine bots look for this text file, so it is a good idea to have one even if it is empty.
The robots make a list of all the links on a page and store them. They also follow each link to the website or page it leads to.
All of this information is then sent to the search engine by the robots. The search engine then takes the information from all of the bots and uses it to build its database. Search engine engineers already help with this part of the process. They write the algorithms that are used to evaluate and score the information that the search engine bots gathered. As soon as all of the information is added to the search engine's database, this information is already available to people using the search engine to do searches.
