Note that every wiki page, and indeed every webpage, is implicitly the AuthorizedCopy of that page, and the authorization mechanism is whatever procedure is required to change that page. However, the term should properly be used for a less trivial authorization mechanism than "anyone who can hit Save". For a community that cares about the message it authorizes, this mechanism will become increasingly important. For instance, very few wikis nowadays do not include some mechanism to block automatic authorization of WikiSpam.
Authorization mechanisms typically try to allow for PeerReview by trusted members of the community. Who is a trusted member, and to what extent they are trusted, forms a TrustMetric in the community. This will ultimately be socially maintained, but typically the metric will be enforced by some mechanical mechanism, e.g. logins and permissions.
Authorization may be "modal", using a less rigorous mechanism for some pages, with one or more more stringent mechanisms held in reserve for "hot" pages. For instance, WikiPedia defaults to trivial authorization, but hot pages may be locked, at which point only pre-approved administrators may change the page.
Required by: AuthorizedView
See also: StableCopy, WebOfTrust