Of course, there are loads of search engines used globally, such as Yahoo, Bing, Yandex, DuckDuckGo. So why are we focusing on Google in this guide? Think about a time you had a problem or question, what search engine did you use? The chances are you Googled it! The chances of your customers using Google are high, right? And the number one rule of marketing is to know your customer. Therefore it makes sense from a marketing point of view, why ranking high on Google is important. You want to be where your customers are.
Please note, in some countries Google may not be the most used search engine, such as in China or Russia. It is important to research the most used search engine in the country where your customers reside in as part of your SEO strategy.