# What is the Wayback Machine, and how can it help you check a source?

Date: 2021-10-24 · Author: Robert Scales · https://guidetoartificialintelligence.com/en/learn/what-is-the-wayback-machine/

**Answer:** The Wayback Machine is the Internet Archive's free service for viewing old copies of web pages: you type an address, pick a date, and browse the page as it looked then. It opened to the public 20 years ago today, on October 24, 2001, with more than 10 billion pages saved since 1996, and it is still one of the best tools for checking what a source said and when.

Twenty years ago today, on the evening of October 24, 2001, the Internet Archive opened its collection of old web pages to everyone. The service was unveiled at a ceremony at the Bancroft Library of the University of California, Berkeley, and put online at web.archive.org under a playful name: the Wayback Machine. Anyone could now type a web address, choose a date and see that page as it was.

For five years the Archive had been copying the public Web, but the copies sat mostly on digital tape, and only some researchers could get at them. The Wayback Machine turned a store room into a reading room. For anyone who checks facts, including facts that come from AI tools, it is still one of the most useful free services online.

## What did the Archive launch in 2001?

The Archive's press release, dated October 24, 2001, called the Wayback Machine a free service for viewing archived versions of past web pages. The collection went back to 1996 and held more than 10 billion pages, about 100 terabytes of data, and it was growing by roughly 10 terabytes a month. The release said this was more data than any library in the world held, the Library of Congress included.

Brewster Kahle, who founded the Archive, explained the timing: the Archive was turning five, and opening the collection to the public was the way to mark it. The Archive also listed its partners, among them the Smithsonian Institution and the Library of Congress, and supporters such as Alexa Internet, a web-crawling company.

Paul Grabowicz, an assistant dean at Berkeley's journalism school, described old websites as "first drafts of history", a record of how the media and the public reacted to events as they happened.

## How does the Wayback Machine work?

Behind it is a crawler, a program that visits pages, saves them with the date, follows their links and comes back later for newer copies. The Wayback Machine is the front door to that collection. It indexes every saved copy by address and by date, so one page can have many versions over the years.

Using it takes three steps, the same ones the 2001 release described:

1. Go to web.archive.org and type the address of a page into the search box.
2. Pick a date from the copies the Archive holds for that address.
3. Read the page as it was saved then, and click its links to keep browsing the archived Web from that moment.

You can also ask the Archive to save a page now by entering its address, as long as the site allows the crawler in. Not everything is there: pages behind logins, many database results and sites that block crawlers are missing.

## Why does a dated copy matter?

Most of the Web has no memory. A company edits a policy page, a news site corrects a story, a blog shuts down, and the old text is simply gone. A dated copy lets you answer two questions that are otherwise impossible: what did this page say, and when did it say it?

That matters more as AI tools become common. Language models are trained on large snapshots of web text, and they often repeat claims or point to pages that have since changed or disappeared. The table shows what an archive can and cannot settle:

| Question | Can the Wayback Machine help? |
|---|---|
| Did this page ever say that? | Yes, if a copy exists from the right period |
| When was the wording changed? | Often: compare copies from different dates |
| Is the claim on the page true? | No: an archive shows what was said, not whether it is correct |
| Does a dead link still have content somewhere? | Often: look up the exact address |

> **Try it:** Choose a page you rely on, such as your bank's fee page or a company's privacy policy. Look it up in the Wayback Machine, open the oldest copy and the newest one, and write down one change between them and the dates of both copies.

## How can you use the Wayback Machine to check what a source really said?

Start with the exact address. When an article, a report or a chatbot answer cites a page, copy the full link and paste it into the Wayback Machine. If the live page no longer says what was claimed, look at the copies from around the date of the citation; the date on each copy tells you when the crawler saw that version.

Then compare instead of trusting one snapshot. Open two or three copies from different dates and look for the sentence in question. If it appears in one version and not the next, you have found when it changed. Keep the archived address, which includes the date, as your own citation, so anyone can see the same version you saw. That habit turns a vague "I read it somewhere" into a record anyone can check.

## Sources

- Internet Archive Launches Wayback Machine: https://web.archive.org/web/20011201220833/http://www.archive.org:80/wayback/press_kit/press_release.html
- Wayback Machine: https://en.wikipedia.org/wiki/Wayback_Machine