What it is — briefly

The “internet” is a global system of interconnected computer networks that use a common set of protocols (notably TCP/IP "Transport Control Protocol / Internet Protocol") to communicate. It grew from experimental research into resilient, packet-switched communications into a worldwide public and commercial service — and then into the cat-video economy.

Key milestones

1. 1960s — Packet switching theory

   Researchers such as Paul Baran (Bell Labs, USA) and Donald Davies (NPL, UK) independently developed the idea of splitting information into small “packets” to increase resilience and efficiency. These ideas underpinned the later networks.

2. 1969 — ARPANET goes live

   The US Defence Advanced Research Projects Agency (DARPA) connected the first ARPANET nodes (UCLA, SRI, UCSB and the University of Utah) in 1969. ARPANET demonstrated packet-switched networking and remote resource sharing.

3. 1971 — Email appears

   Ray Tomlinson sent the first networked e-mail on ARPANET, introducing the use of the “@” sign to separate user and host — a small character, a huge cultural impact.

4. 1973–1974 — TCP/IP designed

   Vint Cerf and Bob Kahn published the seminal TCP paper (1974) describing a protocol suite to interconnect disparate networks — the blueprint for the internet’s packet delivery and addressing approach.

5. 1983 — TCP/IP becomes standard on ARPANET

   On 1 January 1983 the ARPANET formally switched to the TCP/IP protocol suite. This “flag day” is often treated as the birth of the modern internet architecture.

6. 1984 — DNS introduced

   The Domain Name System (DNS) replaced numeric addressing with human-friendly domain names (like example.com), making the network far easier to use and scale.

7. 1989–1991 — World Wide Web

   Tim Berners-Lee at CERN proposed (1989) and implemented (1990–1991) the World Wide Web: HTML, URIs (URLs) and HTTP, along with the first browser and server. The Web made the internet accessible to non-specialists.

8. 1993 — Mosaic browser

   The Mosaic browser popularised graphical web browsing and helped trigger the web’s rapid public adoption and commercialisation in the mid-1990s.

9. Mid-1990s — Commercial growth

   By 1995 the web had moved from research and hobbyist uses into mainstream commercial services, ISPs, portals and e-commerce. The “dot-com” boom followed.

10. 1998–2000s — Search engines and social platforms

    Google (founded 1998) transformed web search. The 2000s saw the rise of social networks, user-generated content platforms and increasingly sophisticated web services.

11. 2007 onwards — Mobile and broadband ubiquity

    The smartphone era made the internet truly ubiquitous. Faster broadband, Wi-Fi and mobile networks turned the internet into an anytime, everywhere utility for billions.

Who built it (short list)

Why it mattered

Beyond convenience, the internet reshaped commerce, media, research and social life. It replaced centralised gating with standards and protocols that let many independent networks interconnect — a design decision that encouraged innovation (and occasional chaos).

The Three Layers

• Surface web (public) — Roughly 4–10% of all internet content. These are the sites you can find through search engines: news pages, blogs, shops, cat memes. It’s the tip of the iceberg — highly visible but small.
• Deep web (commercial, academic, private) — Around 90%+ of the internet. This includes databases, subscription-only content, intranets, private social media posts, government records, academic journals, and medical information. Perfectly legal, just not indexed by search engines.
• Dark web — Estimated 0.01–0.1%. Accessible only through tools such as Tor. Some of it is criminal marketplaces, but it also hosts whistleblowing platforms, forums in restrictive countries, and privacy-focused services. Think of it as the dimly lit basement of the internet.

Visual breakdown

Why so much is hidden

Most internet content isn’t secret — it’s simply locked away behind logins, paywalls, or structured databases that search engines can’t index. For example, airline booking systems, online banking records, and university databases all live in the “deep” part of the web.

So what do we actually use?

Everyday users mostly inhabit the surface (for browsing) and the deep web (for emails, banking, social media accounts). Only a tiny fraction venture into the dark web — and most who do are there for anonymity and privacy, not cloak-and-dagger dealings.

Not the same as the Internet

The Internet is the giant plumbing system of cables, routers and servers connecting computers across the globe. The World Wide Web (WWW) is a service that runs on top of it — a way of linking and sharing information using web pages, browsers and links. In other words: the Internet is the motorway network, the Web is the cars, lorries and caravans travelling on it (and sometimes breaking down in the middle lane).

A quick history

• 1989: Tim Berners-Lee, working at CERN in Switzerland, proposed a system for sharing documents across research institutions. He called it the “World Wide Web”.
• 1990–1991: He built the first web server, browser, and page. The first website explained… how to make websites. Very meta.
• 1993: The Mosaic browser arrived, adding images and easy navigation. Suddenly the Web wasn’t just for scientists, it was for everyone.
• Mid-1990s: Netscape Navigator, Microsoft Internet Explorer and a growing web of sites fuelled the “dot-com boom”.
• 2000s onwards: The Web evolved into today’s interactive, social, video-filled world — no longer just documents, but platforms, shops, and cat videos galore.

How does it work? (Layman’s edition)

Imagine the Web as a giant library that anyone can add books to, and anyone can read from, provided they know where to look. Here’s the recipe:

1. Addresses (URLs): Every web page has a unique address, a bit like a house number plus street name. Type it in, and your browser knows where to knock.
2. Browsers: Your browser (Chrome, Safari, Firefox) is like a friendly librarian who fetches the right book when you ask for it.
3. Web servers: These are the “houses” or “bookshelves” where the web pages actually live. When you request a page, the server sends it back to your browser.
4. Protocols (HTTP/HTTPS): Think of these as the polite language rules — the “please” and “thank you” — that browsers and servers use so they can exchange information without shouting at each other.
5. Hyperlinks: The magic glue. A link is like a library index card that says, “If you liked this, you might also want to look over there.”

Put all that together, and you have a system where clicking a blue underlined word can whisk you halfway around the world in less than a second — no passport required.

Why it took off

The Web exploded in popularity because it was open, simple, and free to use. Anyone could set up a website, and anyone could link to it. That openness created an ever-expanding mesh of information, commerce, entertainment and nonsense that we now can’t live without.

What is an IP address?

An IP address (Internet Protocol address) is a unique number assigned to each device connected to a network that uses the Internet Protocol. Think of it as the postal address for your computer, phone, or even your smart fridge — without it, data would get hopelessly lost.

Why they matter

Every email, cat meme, or online shopping order has to travel from one device to another. An IP address ensures the information knows where to go and where it came from. Without IP addresses, the Internet would be like trying to post a letter without writing the recipient’s or sender’s address — Royal Mail would not be impressed.

A short history

• 1970s: IP addressing was defined during the creation of the Internet Protocol itself as part of ARPANET’s evolution.
• 1981: IPv4 was standardised (32-bit addresses, about 4.3 billion possible). At the time, that seemed more than enough — who could possibly need billions of addresses? (Answer: us, quite quickly.)
• 1990s: The Internet exploded. Address shortages became apparent. Work began on a bigger system: IPv6.
• 1998: IPv6 was defined (128-bit addresses, roughly 340 undecillion possibilities — that’s a number so big it’s basically “more than enough”).
• 2010s: The world started running out of free IPv4 addresses. IPv6 adoption has grown steadily since, though many networks still run both.

IPv4 vs IPv6

IPv4 looks like 192.168.1.1 — four numbers separated by dots, each between 0 and 255.

IPv6 looks like 2001:0db8:85a3:0000:0000:8a2e:0370:7334 — longer, trickier to read, but virtually inexhaustible.

Public and private addresses

Not all IP addresses are visible to the outside world. Some ranges are reserved for private networks (like 192.168.x.x) used in homes and offices. Your router usually has a public IP for the Internet and hands out private IPs to devices indoors — a bit like a receptionist forwarding calls.

In everyday use

When you type a website name, your computer quietly looks up the site’s IP address using DNS (the Internet’s phone book). You rarely see the numbers yourself, but they’re always working in the background, making sure Netflix lands on your TV and not your neighbour’s toaster.

What’s a domain?

A domain name is a human-friendly label that points to an Internet resource. Instead of typing 142.250.187.46, you type google.com. Much easier to remember, and far less likely to make your brain melt.

Domains are hierarchical. Take www.bbc.co.uk for example:

• .uk — the top-level domain (TLD)
• .co — a second-level domain (usually indicates type of organisation)
• bbc — the registered domain name chosen by the organisation
• www — a subdomain, often used for the main website

Put together, they form a neat address that’s both unique and memorable.

What’s DNS?

DNS (Domain Name System) is the Internet’s phone book (or directory enquiries, if you remember those). When you type in a domain name, your computer asks DNS, “Excuse me, what’s the IP address for this site?” and DNS replies with the right number.

How DNS works (in simple steps)

1. You type example.com into your browser.
2. Your computer checks its local cache (has it looked this up recently?).
3. If not, it asks a DNS resolver (usually run by your ISP or a public service like Google DNS).
4. The resolver contacts the root servers (which know where the top-level domains live).
5. The root says, “.com servers are over there.”
6. The resolver then asks the .com servers, “Where is example.com?”
7. They point to the authoritative server for example.com.
8. The authoritative server replies, “It’s at 93.184.216.34.”
9. Your computer now knows the IP and connects to the website.

All this usually happens in milliseconds — faster than you can say “why is my Wi-Fi slow?”

A touch of history

• 1983: DNS was introduced, replacing a single centralised hosts.txt file that listed all known computers. (Yes, people actually updated a text file for the Internet. It didn’t scale well.)
• 1985: The first domains were registered: symbolics.com was the very first.
• Today: There are over 1,500 top-level domains, from classics like .org to newer ones like .pizza and .ninja.

Why it matters

Without domains and DNS, the Internet would be a jungle of unmemorable numbers. They make the web usable, brandable, and navigable — whether you’re visiting a government site, your favourite shop, or catsareawesome.pizza.