The Long Journey of Email — From ARPANET to 400 Billion Letters a Day

When I was a young clerk, the senior postmaster told me that the postal system was older than the country itself. "People needed to send messages before they needed almost anything else," he said. That stuck with me. And when I look at the story of email, I see the same truth — the desire to send a message to someone came before the web, before browsers, before almost everything we associate with the internet today.

Let's walk through this history together, one era at a time. This one takes a second cup of tea.

1965 — The Mailbox on a Shared Desk

Before email crossed any network, it lived inside a single machine. At MIT, a system called MAILBOX was part of the Compatible Time-Sharing System (CTSS). It allowed users who shared the same computer to leave messages for each other — like leaving a note on a colleague's desk. It wasn't networked. It wasn't fast. But it was the seed of something much bigger.

Think of it as the suggestion box nailed to the wall of a single office — useful, but limited to whoever walked through that door.

Reference:

• The History of Email — Cloudflare Blog

1971 — The First Letter Crosses the Wire

This is the moment everything changed.

Ray Tomlinson, an engineer at Bolt, Beranek and Newman (BBN), was working on ARPANET — the U.S. government's early computer network that connected roughly fifteen machines across laboratories in the country. Tomlinson had written a file transfer program called CPYNET. One day, he had the idea to combine it with SNDMSG, a local messaging tool, so that a message could travel from one computer to another across the network.

Sometime in late 1971, he sent a test message between two PDP-10 computers sitting side by side, connected through ARPANET. He couldn't even remember what it said — possibly "QWERTYUIOP" — because at the time, it didn't feel momentous. He later told a colleague, "Don't tell anyone! This isn't what we're supposed to be working on."

But the most lasting part of his work? He chose the @ symbol to separate the user name from the host name. He picked it because it was the least-used character on his Model 33 Teletype — and it conveniently meant "at." That convention has never changed.

Here's the remarkable thing: the World Wide Web wouldn't be proposed until 1989, and HTTP wouldn't be functional until 1990–1991. Email predates the web by nearly two decades. People were sending electronic letters long before anyone could browse a web page.

References:

• Ray Tomlinson — Wikipedia
• History of Email — Wikipedia
• The First E-mail Message of Ray Tomlinson — History Tools

1973 — Email Becomes the Main Event

Only two years after Tomlinson's experiment, a study commissioned by ARPA found that 75% of all ARPANET traffic was email. The network had been built for sharing computational resources and research data — but it turned out that people mostly wanted to talk to each other.

This is something I understand deeply. We built post offices to handle government correspondence and commercial shipments. But what filled our bags every day? Birthday cards. Love letters. Notes between friends.

At this point, email was basically hitchiking on the File Transfer Protocol. It was piggy-backing on FTP using the MAIL and MLFL commands. If you happen to read ancient text on the FTP, remember this.

Reference:

• The Origins of E-mail — Stanford University

1976 — A Queen and a Campaign

On March 26, 1976, Queen Elizabeth II of the United Kingdom sent an email from the Royal Signals and Radar Establishment in England over the ARPANET — making her the first head of state to send an electronic message.

That same autumn in the US, Jimmy Carter's presidential campaign became the first political campaign to use email for internal communications.

Even in the 1970s, it was clear: email wasn't just for engineers anymore.

Reference:

• History of Email — Wikipedia

1978 — The First Unwanted Delivery

In May 1978, a marketer named Gary Thuerk at Digital Equipment Corporation sent an unsolicited promotional email to roughly 400 ARPANET users. He claimed it generated $13 million in sales. It also generated immediate backlash — an ARPANET representative asked him to never do it again.

Every postmaster has dealt with junk mail. But this was the first piece of digital junk mail — and it arrived only seven years after the first email itself.

Reference:

• History of Email Spam — Wikipedia

1982 — The Postal Routes Get Formalized (SMTP, RFC 821 & RFC 822)

By the early 1980s, email had been riding on the back of the File Transfer Protocol (FTP) — like a letter hitching a ride on a freight truck. It worked, but it wasn't designed for the purpose.

In August 1982, Jon Postel published RFC 821, which defined the Simple Mail Transfer Protocol (SMTP) — the dedicated postal route for email. No more hitchhiking. Email had its own delivery system now.

At the same time, Dave Crocker authored RFC 822, which defined the standard format for email messages — the headers, the addressing, the structure. Think of RFC 821 as the postal truck, and RFC 822 as the standard envelope: where to write the address, where to put the return address, how to format it so any post office can read it.

On January 1, 1983, ARPANET switched from NCP to TCP/IP, and the modern internet began to take shape. Email was ready.

References:

• History of Email — Wikipedia
• RFC 821 — SMTP
• RFC 822 — Standard for the Format of ARPA Internet Text Messages

1991–1992 — Email Learns to Carry Packages (MIME)

In the early days, email could only carry plain ASCII text — the equivalent of a handwritten note on a blank piece of paper. No images, no attachments, no characters beyond the English alphabet.

In 1991, Bell Communications proposed MIME (Multipurpose Internet Mail Extensions), which moved to the RFC stage in 1992 as RFC 1341 (later refined as RFC 2045–2049). MIME gave email the ability to carry attachments — images, audio, documents — and support non-ASCII text, which meant people in Japan, Korea, the Middle East, and everywhere else could finally write emails in their own languages.

As a postmaster, this is like the day we started accepting parcels, not just letters. The whole nature of the service changed.

References:

• RFC 2045 — MIME Part One
• When Email Was Invented — Mutant Mail

1991 — Meanwhile, the Web Is Born

Just to put things in perspective: in 1989, Tim Berners-Lee proposed the World Wide Web at CERN. In 1990, he built the first web browser and server. In August 1991, the web was made available to the public.

By that time, email had been running for twenty years. It had protocols, standards, and millions of users. The web was the newcomer. Email was the elder.

References:

• A Short History of the Web — CERN
• Evolution of HTTP — MDN

1993–1996 — Email Comes to Everyone

The early 1990s were transformative. Before 1993, you needed a dedicated software program installed on your computer to send and receive email. Then webmail arrived — the idea that you could access your inbox through a browser.

In 1993, CERN saw the first prototype of web-based email (though it was never released publicly). AOL and Delphi connected their proprietary email systems to the internet, opening the floodgates.

Hotmail launched in 1996 as one of the first free, web-based email services — you could check your mail from any computer. Yahoo Mail followed in 1997. Email was no longer tethered to a single machine. It was like being able to walk into any post office in the country and pick up your mail.

References:

• History of Email — Mailmeteor
• History of Email Marketing — Knak

2003 — Fighting Back Against Junk Mail (CAN-SPAM Act)

By the early 2000s, spam had become a crisis. In the United States, the CAN-SPAM Act was signed into law in 2003, establishing rules for commercial email — including the requirement for an unsubscribe mechanism and truthful header information.

Around the same time, authentication protocols began to emerge. SPF (the approved courier list), DKIM (the wax seal), and eventually DMARC (the policy manual) gave the email world tools to verify that a message really came from who it claimed to be.

It took the postal system centuries to build trust and verification. Email had to figure it out in a few decades — and the work continues today.

Reference:

• The History of Email Spam — Knak

2004 — Gmail Changes the Game

On April 1, 2004, Google launched Gmail — and many people thought it was an April Fool's joke. It offered 1 GB of storage at a time when competitors offered a fraction of that. It introduced threaded conversations, powerful search, and eventually a tabbed inbox.

Gmail showed the world what a modern post office could look like: organized, searchable, and spacious. Today it has roughly 1.8 billion active users.

Reference:

• The History of Email — Email on Acid

2007 — The Post Office in Your Pocket

The introduction of the iPhone in 2007 changed email again. Suddenly, your inbox was always with you. Mobile optimization became essential — emails had to look good on a small screen. The way people read and responded to mail shifted fundamentally.

Today, roughly 61% of people check email primarily on a mobile device. The post office isn't a building anymore — it's in your hand.

Reference:

• Email Usage Statistics — EmailTooltester

Key RFCs — The Rule Books

For those who like to see the official documents, here are the most important RFCs that define how email works from IETF Datatracker:

2025 — Where We Are Today

As of 2025, approximately 376 billion emails are sent and received every single day worldwide. There are around 4.6 billion email users — more than half the world's population. By 2027, daily email volume is projected to exceed 400 billion.

In 1971, Ray Tomlinson sent a forgotten test message between two machines sitting side by side. Today, humanity sends more emails in a single day than there are stars in the Milky Way.

And yet, the fundamentals haven't changed all that much. We still use SMTP. We still use the @ symbol. The message still travels from sender to recipient, through routing and sorting, just like a letter through the postal system.

References:

• How Many Emails Are Sent Per Day — EmailTooltester
• Email Statistics — Statista

Every letter matters to someone. That was true in 1971, and it's true today. The technology evolved — from ARPANET to the cloud, from ASCII-only text to rich media, from a few hundred researchers to billions of people — but the purpose never changed. Someone writes a message. Someone else receives it. And somewhere in between, a system works quietly to make sure it arrives.

Take your time with this history. There's no rush. The mail will wait.