Unlike traditional encyclopedias, Wikipedia allows outside editing: except in particularly sensitive and/or vandalism-prone pages that are "protected" to some degree,[24] even without an account readers can edit text without permission. Different language editions modify this policy to some extent; for example, only registered users may create a new article in the English edition.[25] No article is considered to be owned by its creator or any other editor, nor is it vetted by any recognized authority. Instead, editors are supposed to agree on the content and structure of articles by consensus.[26]

By default, an edit to an article immediately becomes available. Articles therefore may contain inaccuracies, ideological biases, or even patent nonsense until or unless another editor corrects them. Different language editions, each under separate administrative control, are free to modify this policy. For example, the German Wikipedia maintains "stable versions" of articles,[27] which have passed certain reviews. Following the protracted trials and community discussion, the "pending changes" system was introduced to English Wikipedia in December 2012.[28] Under this system, new users' edits to certain controversial or vandalism-prone articles would be "subject to review from an established Wikipedia editor before publication".

The software that powers Wikipedia can aid contributors. The "History" page of each article records revisions (though a revision with libelous content, criminal threats, or copyright infringements may be retroactively removed).[29] Editors can use this page to undo undesirable changes or restore lost content. The "Talk" pages associated with article as well as talk pages that are specific to particular contributors help coordinate work among multiple editors.[30] Importantly, editors may use the "Talk" page to reach consensus,[31] sometimes through the use of polling.

Editors can view the website's most "recent changes", which are displayed in reverse chronology. Regular