What Is a Search Engine?

Definition & Examples of a Search Engine

Person using search engine on their smartphone

Dilok Klaisataporn / EyeEm / Getty Images 

A search engine is an internet program that collects and organizes content according to a user's query. For instance, a person who performs a search engine search for "restaurants near me" would (ideally) see a list of websites that belong to restaurants in that person's area.

While search engines are extremely complex programs, it isn't hard to understand the basic concepts that drive them. Here's how search engines work and some examples of the most popular search engines people use.

What Is a Search Engine?

A search engine is a cornerstone of the internet. For many, a search engine is their starting place whenever they open a web browser. If you don't know the exact address of a website you want to visit—or if you don't know the exact website you want to find—you'll use a search engine to find it.

At its heart, a search engine is simply an internet-based computer program. There are three main functions of this program: collecting massive amounts of information about what is on the internet, categorizing that information, and helping users search through that categorized information.

How Does a Search Engine Work?

To start understanding how search engines work, break down each of its three main functions individually.

First, search engines collect information through a process known as "crawling." "Web crawlers," software designed by the search engine, methodically inspect URLs. These crawlers take in information from hundreds of billions of websites, assessing aspects of a website like the backend code and the copy that visitors read when they land on the webpage.

From there, the information is indexed according to keywords, how recently the site was published, and other factors.

Once the information is indexed, users can search through that index by typing a query into the search bar. These searches trigger complex algorithms that sift through the massive index to find the most relevant results. When you submit a query, the algorithm simultaneously assesses the meaning of your query, the relevance of indexed webpages, the quality of the content on those webpages, the functionality of those webpages, and the context of your search (the location from which you performed the search, your search history, etc.).

Motivations Behind Search Engines

It's helpful to look at the motivation behind searching from three different perspectives.

  • The searcher: This is the person who is on the web searching for information, products, or services. They want to enter some keywords that represent that information, product, or service and have relevant websites quickly appear that effectively meet their needs.
  • The search engine: The search engines are making money selling ad space to websites, businesses, and marketers. The more search traffic they can generate, the more eyes on their ads, and the more money that is made. Their goal is to have the most relevant sites pop to the top of search results. That way, searchers find what they want and develop a positive relationship with the search engine. The next time they want to perform an internet search, they'll (hopefully) return to that search engine.
  • The website or marketer: They want these web searchers to find their site when they're searching for relevant keywords so that they can promote their products or services.

It's all about the content of the page matching what the searcher wants, which makes them happy so they return to the same search engine next time, which makes the engine happy. When a searcher finds a website they like, that website is happy because it is receiving more traffic from potential customers.

Most Popular Search Engines

By all measurements, Google is the most popular search engine, and its name has become synonymous with performing search engine queries ("Googling" something). However, it isn't the only search engine. Internet users have plenty of options. Here is a breakdown of some of the most popular search engines by market share, as recorded by NetMarketShare in July 20200:

  • Google: 83.86%
  • Baidu: 7.01%
  • Bing: 6.14%
  • Yahoo!: 1.34%
  • Yandex: 0.85%

While searchers should feel free to explore their options, businesses and marketers should pay attention to which search engines are the most popular. There's no use spending all your advertising budget on a search engine that is hardly used.

Search Engine Optimization

Search engine optimization (SEO) is the act of trying to improve a website's performance on a search engine. For businesses that want to effectively use their website to drive sales, a solid SEO strategy is crucial.

If your website doesn't land on the first few pages of a relevant search engine result, then it's unlikely that a customer will find your site through that search engine. For example, if you run a real estate business in Miami, Florida, you want to focus your SEO efforts on ensuring that your site appears when people search "real estate in Miami" on a search engine.

Key Takeaways

  • Search engines are programs that make it easy for people to search the internet for a relevant web page.
  • The three main functions of a search engine are collecting information about webpages, categorizing those webpages, and creating an algorithm that makes it easy for people to find relevant web pages.
  • Google is by far the most well-known search engine.
  • When a website attempts to improve its performance on a search engine, this is known as search engine optimization (SEO).