Ever wondered how a search engine comes up with the exact results when you type something in its query box? After all, there are trillions of results matching your search query. A fascinating process is at work behind it, something you would be very interested to learn about. Also, understanding how the search and index factors work would help you relate to your customers in a better way. A web crawler is a program that acts as an automated script which browses through the internet in a systematic way.