Developing a search engine is complicated and requires a demanding amount of resources. Long before Google started hosting vast amounts of data in Gmail and Google Drive, the company needed to invest heavily in infrastructure just to sustain their initial search service. Suffice to say, most people cannot design and maintain their own web search engines, and there is a reason only a few key players dominate the arena. Yet regardless of which search provider you turn to, the process for how search engines work is largely the same.
1. Crawling
First, developers create Internet bots capable of reading hyperlinks and HTML. These web crawlers browse the Internet looking for web sites in order to index them. They are provided with a list of URLs to start with, and the bot scans all of the hyperlinks on each of these pages and adds them to the list of URLs to visit next. Crawlers can only download a certain number of pages within a given time period, which is why search results sometimes suggest websites that have since been deleted or removed. The websites these web crawlers visit are indexed according to the information the bots can gather by reading each site’s HTML.
2. Indexing
Indexing speeds up the process of retrieving relevant webpages. Searching an index is a substantially less intensive and time-consuming task than searching all of the possible websites. Imagine having to send out new web crawlers to discover the answers to every search inquiry. It would be akin to sending explorers out into the wilderness blind rather than using a map.
Indexes must be stored, and considerable time and effort goes into keeping indexes up-to-date, but the trade-off in speed makes the effort worth it.
3. Searching
Searching is the most visible step of the process. When you type a term into Google, Bing, Yahoo, Duck Duck Go, or any number of search engines, they search their respective indexes for the best results. This information is then displayed on search engine results pages (SERPs).
4. Making Money
Since search engines are free, how were some able to grow into such massive companies? Like much of the Internet, search engines make money by selling ad space. Some advertisers pay to have their products or services ranked higher in search results. Some engines, such as Google, run search-related ads alongside their general search results. As search engines became the most popular way of finding information on the internet, they also became the most popular way of advertising online. Potential consumers may not read the same websites, but they do turn to the same search engines.
Final Thoughts
The process is immensely complex, and there is a great demand out there for people who understand the intricacies of how search engines work. This guide just scratches the surface, but there’s a wealth of information out there. Thanks to search engines, finding that information is easier than ever.
