.com - commercial business.Originally, .com was meant to represent commercial or business website. However, it now represents just about anything under the sun. This is by far the most popular and the most recognizable of the domain name extensions. The .com domain extension is the best choice for offline advertisement, too.
.net - Network organizations. It is most commonly used by Internet service providers, Web-hosting companies or other businesses that are directly involved in the infrastructure of the Internet. Additionally, some businesses choose domain names with a .net extension for their intranet Websites.
.org - Organizations (nonprofit): It is primarily used by non-profits groups or trade associations.
.edu- Primarily used for Educational institutions