A revert is to undo all changes made after a certain time in the past. The result will be that the page becomes identical to how it used to be at some previous time.
Reverting is used primarily for fighting vandalism.
- Sam Hocevar's godmode-light.js script adds functionality similar to the admin rollback links described below. More info at WP:US.
- The vandal edit can also be reverted using popups.
On the User Contributions page an admin has additional "rollback" links at lines which are the last edit made by anybody to that article.
The rollback link is also shown on the Diff page when viewing the difference between the most recent version of a page and the last version.
Clicking on the link reverts to the previous edit not authored by the last editor, with an automatic edit summary of "Reverted edits by X to last version by Y".
If, between loading the User Contributions page and pressing "rollback", someone else edits or rolls back the page, or if there was no previous editor, you will get an error message.
This feature's function is best described by developer Brion Vibber in this posting:
No one should ever be in an edit war, sysops in particular should be aware that that's not cool, so there's no need to think about whether or not 'rollback' should be used in an edit war. It shouldn't, because we shouldn't be in that position in the first place.
Rollbacks should be used with caution and restraint. Reverting a good-faith edit may send the message that "I think your edit was no better than vandalism and doesn't deserve even the courtesy of an explanatory edit summary." It is a slap in the face to a good-faith editor; do not abuse it.
If you use the rollback feature other than against vandalism or for reverting yourself, be sure to explain on the talk page of the user whose edit(s) you reverted.
In cases of flood vandalism, admins may choose to hide vandalism from recent changes. To do this, add &bot=1 to the end of the url used to access a user's contributions. For example, http://en.wikipedia.org/w/wiki.phtml?title=Special:Contributions&target=SomePersistentVandal&bot=1.
When the rollback links on the contributions list are clicked, the revert, and the original edit that you are reverting will both be hidden from recent changes unless you click the "bots" link to set hidebots=0. The edits are not hidden from contributions lists, page histories or watchlists. The edits remain in the database and are not removed, but they no longer flood Recentchanges. The aim of this feature is to reduce the annoyance factor of a flood vandal with relatively little effort. This should not be used for reverting a change you just don't like, but is meant only for massive floods of simple vandalism.
Revert wars considered harmful (the three revert rule)
Wikipedia policy states that you may not revert any article more than three times in the same day. This is a strict limit, not a given right; you should not revert any one article more than three times daily. See Wikipedia:Three revert rule for details on this.
High-frequency reversion wars make the page history less useful, waste space in the database, make it hard for other people to contribute, and flood recent changes and watchlists. Sock puppets may not be used to violate this rule. Please request protection rather than reverting. Violation of this rule may lead to protection of the page on the version preferred by the non-violating party; blocking; or investigation by the Arbitration Committee.
Being reverted can feel a bit like a slap in the face—"I worked hard on those edits, and someone just rolled it all back". However, sometimes a revert is the best response to a less-than-great edit, so we can't just stop reverting. What's important is to let people know why you reverted. This helps the reverted person because they can remake their edit, but fixing whatever problem it is that you've identified.
Explaining reverts also helps other people. For example, it lets people know whether they need to even view the reverted version (in the case of, eg, "rv page blanking"). Because of the lack of paralanguage online, if you don't explain things clearly people will probably assume all kinds of nasty things, and that's one of the possible causes for edit wars.
If your reasons for reverting are too complex to explain in the edit summary, drop a note on the Talk page. A nice thing to do is to drop the note on the Talk page first, and then revert, rather than the other way round. Sometimes the other person will agree with you and revert for you before you have a chance. Conversely, if someone reverts your change without apparent explanation, you may wish to wait a few minutes to see if they explain their actions on the article's talk page or your user talk page.