Search engine optimisation (SEO)

Types of search engine


Different types of search engines use different methods to rank websites. Understanding these methods will help you understand the SEO strategies outlined in this guide.

Popular search engines

The three of the most popular search engines are:


Google assesses the value of a webpage based on the number of backlinks ie links back to your website. Links from pages that are seen as important by Google weigh more heavily and increase the ranking of the linked pages. Google also analyses the relevancy of the content on the page and other factors like mobile-friendliness. The Google ranking algorithm changes constantly. It can be useful to keep up to date with the latest changes. 


Microsoft's Bing search engine ranks websites based on the webpage content, the number and quality of websites that link to your pages, and the relevance of your website's content to keywords.


Yahoo! is now powered by Bing. 

Google has the vast majority of the search market share. Bing, Yahoo and others make up a much smaller percentage.

If you are targeting customers in China, keep in mind that Google is blocked by the 'Great Firewall of China'. Baidu is the biggest search engine in China with over 75% of the search market.

These main search engines use 'crawlers' to search the internet. See what is a search engine and how do they work?

For more detailed information on how to best optimise your website for a particular search engine, refer to their webmaster pages. All the leading search engines provide information and tools to help you improve your SEO.

Specialist search engines

There are a number of specialist search engines that allow users to search for specific things like videos, used cars, recipes, flights and hotels. SEO tactics can be used to help your products and services rank well on specialist search engines. Listings on these websites often appear in standard web search results. 

Examples of specialist search engines:


Digital marketers often describe YouTube as 'the second biggest search engine in the world'. Owned by Google, it allows users to search for video content. 


Amazon works as a search engine for products. It is often users' first place to research products on the market. 


Skyscanner allows users to search for flights and compare prices. 


Primarily a social media channel, Facebook receives over 2 billion searches a day, putting it ahead of Bing. Users can search for people, businesses, products and services. 

Many of these niche search engines are directories. This means they rank content that has been manually added. Some may use crawlers to find specific types of content from the internet. See what is a search engine and how do they work?