Someone changed the Wikipedia article about you, or about your company, and you want to know who. The good news is that Wikipedia already keeps that record and makes it public. Nothing has to be requested, and nobody has to be asked. The record is one click away from the article, and most people never look at it because they do not know it is there.
Every edit is recorded
Wikipedia stores a permanent, public log of every change ever made to every article. It is called the page history. Open any article and select the View history tab at the top of the page. What you get is a list, newest first, where each row is a single edit.
Each row carries the same five things:
- the date and time the edit was saved, in your preferred time zone
- the account name of the editor, or their IP address if they were not logged in
- the size of the article after the edit, and how many bytes the edit added or removed
- the edit summary, which is a short note the editor may have written to explain the change
- links to compare that version against others
This record goes back to the article’s first version. An article created in 2004 still has its 2004 edits listed, along with every change since. Wikipedia does not prune history, and edits cannot be quietly removed by the person who made them.
Reading the history page
The two links on each row, prev and cur, are the ones that matter.
Selecting prev shows you what that single edit changed, compared to the version immediately before it. Selecting cur shows you everything that has changed between that version and the article as it stands right now. If you have been away from a page for six months, cur on the last edit you remember tells you the sum of what happened while you were not looking.
You can also select any two radio buttons in the list and compare those two versions directly. This is how you answer a question like “what did this article say before the reporter called.”
What a diff actually shows
The comparison view is called a diff. It puts the old text on the left and the new text on the right, and highlights only the lines that differ. Removed text appears on the left in one color, added text on the right in another, and unchanged paragraphs are collapsed out of the way.
A diff is the only view that tells you what happened. The byte count in the history list tells you how much changed, which is a different question and frequently a misleading one. An edit that adds 400 bytes might be a new paragraph of sourced biography. An edit that removes 12 bytes might change “was acquitted” to “was convicted.” Size is not severity, and this is the single most common mistake people make when they skim a history page.
Registered accounts and IP addresses
Wikipedia lets people edit without an account. When they do, the edit is logged against their IP address rather than a username, and that IP address is visible to anyone reading the history.
This produces an odd result: unregistered edits are often easier to place than registered ones. An IP address can frequently be traced to a city, an internet provider, or an organization. A registered account, by contrast, shows you only the name its owner chose and whatever they have chosen to say on their user page.
Selecting an editor’s name or IP address takes you to their contributions list, which shows every other edit that account or address has made. This is where a pattern becomes visible. An account whose entire history is edits to one company’s article, made in the week before a funding announcement, is telling you something that no single diff would.
Wikipedia’s own policy on this is worth knowing: editing while logged out to conceal your identity is called sock puppetry, and it is prohibited. That does not stop it happening, but it does mean the community treats the pattern as a problem rather than a quirk.
Edit summaries are a claim, not evidence
The edit summary is free text. The editor writes whatever they want, and nobody checks it against the diff.
Most summaries are honest. Some are careless. A few are deliberately misleading, and “copyedit” or “fixed typo” on an edit that rewrote a paragraph is a recognized pattern rather than a rare one. Read the summary for context and then read the diff to find out what actually changed. If the two disagree, the diff is the fact.
Finding when a specific sentence appeared
Sometimes the question is narrower. A sentence is in the article now, you believe it is wrong, and you want to know when it arrived and who put it there.
Scrolling the history one diff at a time works on a short article and becomes impractical on a long one. The tool built for this is WikiBlame, which searches the revision history for the first version containing a given phrase and returns the revision, the date and the editor. It is linked from the page history itself, under the external tools shown at the top of the history view. XTools, linked from the same place, gives you a statistical view of an article instead: who has edited it most, when activity spiked, and how the article has grown.
What an editor’s other edits tell you
Selecting an account name or IP address in the history takes you to that editor’s contributions, and this is frequently more informative than the edit itself.
Look at three things. How long has the account existed, and what did it do before it found your article? Does it edit across many unrelated topics, which is what an ordinary volunteer looks like, or does its whole history orbit one company, one industry, or one person? And does its activity cluster around dates that mean something, such as a funding round, a lawsuit filing, or a product launch?
An account created in March that has edited nothing but your competitor’s article and yours is making a statement. No single diff would tell you that, and the contributions list makes it obvious in about fifteen seconds.
User talk pages are worth a look too. Every editor has one, and warnings from other editors land there in public. An account that has been cautioned for conflict-of-interest editing or for edit warring carries that record where anyone can read it.
Two things the history will not show you
The record is close to complete, with two gaps worth knowing about.
Deleted and suppressed revisions. Administrators can remove a revision from public view, and a small number of revisions are suppressed entirely for legal or privacy reasons. These are rare, they are logged, and the usual reason is that somebody posted private information or something defamatory that should not stay readable. You will see a gap rather than the content.
Edits to other articles that mention you. This is the bigger one, and almost nobody thinks about it. The history of your article covers your article. It says nothing about the paragraph in your industry’s article, the sentence in the entry about the company you used to run, or the list you were just added to or removed from. Those are separate pages with separate histories, and a change there can matter as much as a change to your own biography.
Where the history stops being enough
The page history answers what changed, when, and who changed it. It is complete, it is public, and it is free.
What it does not do is tell you that something changed. The history is a place you have to go and look at, and nobody checks their own article’s history tab every day for years. The edits that matter are rarely the ones you are expecting, and they do not announce themselves.
Wikipedia offers a partial answer here in the Watchlist, which follows a set of pages for a logged-in user and can send email when one of them changes. It has two limits worth understanding before you rely on it. It sends one email and then stays quiet until you visit the page again while logged in, and it cannot be narrowed to a single article, so turning it on for the one page you care about turns it on for everything you have ever watched. We wrote about why Wikipedia stops emailing you after the first edit in more detail.
That gap is the reason this service exists. We watch the page and email you within 60 seconds of a change, with the diff in the message, so the first time you learn about an edit is not the third time someone mentions it to you. See how it works.