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  • Writer's pictureJohn Shelburne

What's the difference between .com, .org, .io, .ai

Have you ever wondered why some companies use .io or .org or .gov for their website address?

This episode of Command Line Heroes tells a fascinating story:

Back in 1972, the newly-built ARPANET, godfather of our internet, consisted of about 30 computers.

One of the major nodes of that fledgling network was at Stanford Research Institute. That's where information scientist, Elizabeth "Jake" Feinler, worked. She was a wizard of information management, indexing and data organization, were about to become incredibly useful. Because networks require order as they grow–or else they collapse. Douglas Engelbart, the engineer who became famous for his work on human-computer interactions, was then running the Stanford lab.

Engelbart enlisted Feinler, giving her the task of writing a resource handbook for the first demo of the ARPANET.

that was a contact list of technical liaisons and administrative liaisons for all the host sites. Organizing information for a network of 30 computers was easy enough.

This was, after all, just supposed to be a way for researchers to bounce information back and forth between universities. Not a ton of pressure organizing something like that. But–and you're probably ahead of me here–that was about to change.

Try to imagine: a few dozen host sites and a few dozen universities, military bases, and research centers. Each one with different resources. The military sites were way more secure, of course. The university sites were often run by students. There was no consistent organization.

In order for it to be even remotely useful to anyone, they had to know exactly what they were looking for, where that something was, when it was online, and who could give them access. And the only way they could really do that was by getting in touch with Feinler and the Network Information Center, who had all of that information on hand.

That Network Information Center–also called the NIC–was run by the Stanford Research Institute (SRI).

Feinler's project went from a few dozen host sites to thousands in a matter of years. A 2-person operation with 1 telephone and a file folder of index cards turned into an $11-million military project with 6 phone lines ringing off the hook from 5 AM to midnight, every day, for 20 years.

The NIC was essentially serving as Google for the ARPANET.

All of a sudden, it became really complicated to keep track of all the host sites and manually proofing a document, called the host table. It was something that was done twice a week. It was an incredibly tedious, kind-of burnout job. And it became too big for some of the hosts on the network to even be able to download the file from the NIC regularly enough to have updated information.

The host table was the original domain registry for the ARPANET and was just a flat ASCII text file that users could download directly from the NIC servers.

It was literally a spreadsheet listing all the different hosts and their addresses. A “Yellow Pages” for the networked world.

That table became the original WHOIS: a dedicated server at the NIC, where you could look up names and contact information for every authorized user on the network.

The team at the NIC needed a new form of organization for the table. The manual approach of organizing all the network’s users was growing more untenable by the day.

It would be an understatement to say that Paul Mockapetris delivered.

Mockapetris designed The Domain Name System

The Domain Name System (DNS) attaches a word-based address to each numerical IP address.

The addresses are managed by databases hosted on multiple servers — the Domain Name Servers (DNS). By spreading IP resolution across a network of servers, Mockapetris ensured it was possible to resolve URLs and create domain names 24 hours a day.

The DNS delivered several advantages. For starters: it replaced all those numerical addresses with names that humans could remember.

The method he laid out took on the branches of a tree. Though we don’t really think of it this way now, the domain system was developed using a “tree” system, with each node representing a different, increasingly tiny branch.

At the base of the tree were a handful of branches

The Trunk of the tree was the top-level domains.

The branches were individual nodes called secondary domains that could break into thousands and eventually millions.

The leaves on the secondary domains branches were subdomains which were network nodes that could be used for whatever—FTP servers, telnet, Usenet servers, or what have you.

Navigating the internet no longer meant looking up a string of digits on some spreadsheet. By 1986, a few years after the DNS specs came out, the old host table had fallen to the wayside. But that wasn't the only advantage to the new system.

The really important things about the Domain Name System was that people could get their own domain and then manage the names under it. So that for example, MIT came along and we gave them, and whenever they wanted to change their network, they could do that. They didn't have to call up Network Information Center at Stanford and find out that it was only open from 9 a.m. to 5 p.m. They could manage their own space. That was one part of the magic, to let people separately manage their own names and addresses.

The second part of the magic was the system was set up so that it could itself tell a server at UCLA or anywhere else how to find the servers at MIT that had that information.

The first domain name created through DNS was, though the first domain name registered through DNS was, registered on March 15, 1985, by Symbolics Computer Corporation. Five other domains were registered in 1985:,,, and

Read this amazing article on the history of top level domains.

Timeline of the Domain Name

1985: The First .com Domain

On March 15, 1985, the first-ever .com domain was registered. The Massachusetts-based computer manufacturer Symbolics Inc. claimed this historical moment with the creation of This domain remained under the ownership of Symbolics Inc. until 2009 when Investments purchased it. The domain is now a mix of an online museum and an advertising space.

1995: End of Free Domain Registration

Prior to 1995, domain name registration was completely free of charge. However, the landscape shifted when the National Science Foundation granted Network Solutions, a tech consulting firm, the right to charge for domain registration. A two-year domain registration was priced at $100, marking the end of free domain names.

1998: Privatization of the DNS and Formation of ICANN

In response to President Clinton's suggestion, the Department of Commerce issued a proposal for the privatization of the Domain Naming System (DNS) in 1998. Known as the "Green Paper", this proposal aimed to boost market competition and invite international participation. The resulting public criticism led to the creation of the "White Paper", a revised version that addressed most of the initial concerns and subsequently led to the formation of ICANN.

2003: Enactment of the Truth in Domain Names Act

The Truth in Domain Names Act was incorporated into the PROTECT Act of 2003. This legislation stipulated penalties for the creation of misleading domain names, typically ones directing users to pornographic sites without their consent.

2007: Record-Breaking Domain Sale

In 2007, set a record as the most expensive domain ever sold, purchased for a staggering $35 million. Its buyer, Ben Sharples, primarily bought the domain to prevent competitor Expedia from acquiring it.

2012: Unprecedented Domain Registration Spree

April 2012 witnessed an extraordinary event. Domain speculator Mike Mann registered almost 15,000 domain names within 24 hours. When asked why he did it, his response was simple: "I'm just really greedy. I want to own the world."

2013: Exhaustion of Four-Letter .com Domains

In December 2013, domain data analysis startup WhoAPI announced that all possible four-letter .com domain name combinations had been registered, amounting to a total of 456,976 combinations. Notably, all possible combinations of three-character .com domains had already been claimed since 1997.

2014: Introduction of Over 100 New Generic Top-Level Domains

In 2014, over 100 new generic top-level domains (gTLDs) were introduced, exponentially expanding the possibilities for new websites. These new gTLDs included generic words such as .cars and .music, as well as brand names like .apple and .hyundai.


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