DOMAIN NAMES BASICS

Domain names are typically categorized by their extension, which is their identifying code. The three most popular types of Top Level Domains (TLDs), which are domains that are not associated with a country, are:
.COM (Short for .commercial) Domain names with the .com extension are by far the most popular, and can be purchased by any individual or business.
.NET (Short for .network) This domain extension was originally designed to be used by technical Web sites. However, domains using this extension can be registered by anyone.
.ORG (Short for .organization) Originally designated for non-profit firms and any other organizations that did not fit under the .com or .net extension, any individual or business may now register a .org domain name.
There are Country Level Domains, which use country extensions. Each country has its own domain extension. Canada, for example use .ca, the United States of America use .us, United Kingdom - .uk, etc. Most countries have specific rules surrounding exactly who can register domains using their extension and for what purpose; it’s therefore important to look before you leap.
The Internet Corporation for Assigned Names and Numbers (ICANN), the organization responsible for the administration of TLDs worldwide, has recently approved new extensions that are not specific to any country. These are used for Alternative Domain Names, like .areo, .biz, .coop, .info, .museum, .name, .pro. Each has been designed for a specific use, and is accompanied by certain restrictions. You can find more information about these TLDs here: http://www.icann.org/tlds/
Although .com, .net and .org are typically the most visible and talked-about extensions, they are not the only ones available for use. From a functional perspective, country-level domains work just as well as any TLDs. Therefore, don’t necessarily settle for a TLD when you can get a better one using a different extension.