History

In 1984, seven original generic top-level domains were established as a way to loosely classify the emerging variety of Internet content: .com, .org and .net were open to registration, and .gov, .edu, .int and .mil were reserved for institutions affiliated with government, education, international diplomacy and the military, respectively.

Function

"Org" is an abbreviation of "organization." While anyone could and can register a .org domain, it was originally intended for nonprofits, informational entities and similar noncommercial web destinations that didn't "fit" other top-level domains.

Significance

The fact that many nonprofit and philanthropic organizations use the .org domain lends it a certain credibility not associated with other gTLDs. According to the Public Interest Registry, which operates and maintains the .org domain, it is "considered by people around the world to be the domain of trust."

Visibility

While several top-level domains have been established since the mid-1980s, .org remains one of the most familiar, recognizable and in-demand domains available.

Fun Fact

Socially and environmentally conscious engineering and technology concern MITRE was the very first entity to register a .org domain in July 1985.

Source:

Public Interest Registry

PC Magazine Definitions: Internet Domain Name

Internet Corporation for Assigned Names and Numbers