Search Engine

A search engine is a service that allows users to find content on the internet. The user enters a word (called a search term/keyword) or a phrase (called a key phrase) into a search engine and then receives a list of numerous results in the form of websites, images, videos, or other online data available that are relevant to the user's search query. The search engine results page (SERP) is where the user sees the content.

How does a search engine work?

Over the years, search engines have become increasingly complex, but they all do the same thing in essence. Search engines crawl and index all the data on the internet so that when a person searches for something, the search engine can search the indexed data and display the results in order of relevance (ranking).

Crawling

Crawlers (also known as web crawlers or spiders) are programs that constantly search the internet. They are looking for new websites and new links. Crawlers ensure that search engines are up-to-date with relevant websites.

Indexing

After the crawlers have collected the data, it is analysed, organised, and stored in an index. This allows a search engine to find information as quickly as possible.

Searching

When a search engine receives a query, the words must first be translated to match the input with the indexed information. The search engine does this using various techniques. The translation process leads to a rewritten search query that identifies the important parts of the search query, corrects spelling mistakes, and adds synonyms. The search engine then consults its index to find web pages that match the rewritten search query.

Ranking

Search engines use algorithms to display a list of prioritised results based on what they believe is the best answer to your search query.

Types of search engines

Of course, Google is the first thing that comes to mind. Below are the types of search engines.

Regular search engines

Think of Google, Bing, and Yahoo. All three are free to use and are supported by online advertising.

Private search engines

These have become more popular lately due to concerns about privacy caused by the data collection practices of regular search engines. DuckDuckGo for example.

Vertical search engines

Vertical search, or specialised search, is a way to limit your search query to one topic category instead of the entire web. Think of search bars within webshops and search functions within a social media app.