Firstly before starting with common extensions, let's us understand what are extensions and why are they important!

The URL(Unique Resource Locator) is generally can be divided into 4 parts:

1. Protocol - defines the protocol over which the data is being retrieved
2. Domain - used for referencing a web paged similar to an internet address
3. Top-Level-Domain (extension) - the final component of the domain name
4. Sub-folder - used for routing within a web app

An extension is a set of characters followed by the period in the web address, extension is mainly used for designating a category or country code to a web page.

Some of the most common extensions and their significance:

1. .com - It was created with for-profit companies in mind, but it has now evolved into a go-to for extensions.
2. .net - It was initially designed for internet service providers or networks, but it has since grown in popularity as a viable alternative to.com websites.
3. .org - It was created to represent not-for-profit groups, but it is now open to everyone. Many non-governmental organizations, NGOs, politicians and political parties, and internet communities use it as a domain extension.
4. .co - The .co extension was originally designated the country code for Colombia, but has become a popular option for its use in the past years.
5. .us - Unlike the above extensions, this particular extension is reserved only for us citizens and entities of the United States. In the initial stages, it was associated with the U.S. government similar to the .gov extension.

Why are .com extensions more popular compared to others?

As we know we want to use any object or any entity only if we can benefit from it somehow..... We have seen there is extensive use of dotcom extension compared to other domain extensions. Let's see some of the benefits of using dot-com extensions for our web pages:

1. Provides you worldwide access
2. 46% of websites use a .com domain name
3. .com domain highlights the credibility of your brand
4. Search engines sometimes prefer .com more than any other domain
5. Having .com shows that you’re a well-established company

Since the dot-com extensions are most used and most found on the web the SEO of google is also biased towards this extension. Having a dotcom extension increases the chance of the page shown in top recommendations for a web search.