Custom Fields (XenForo 2.1 only)
RC 2 adds the ability to create custom form fields for wiki content, which can be defined in the admin panel, and configured to appear in a variety of locations, such as above the content, in a sidebar widget, or on a new tab.When users edit wiki content, they can enter values for these fields, and the changes will be tracked in the page's history. Missing field values can be inherited from templates.
A more indepth discussion of custom fields can be found here.
Ratings
RC 2 reintroduces a feature that was once in the 3.x series, but has been missing ever since: the ability for users to rate wiki content from 1-5 stars. Ratings for pages are weighted; a rating for the current edit is considered more valuable than a rating made 5 edits ago. In this way, eventually ratings fade away, so users should be encouraged to rate and re-rate content frequently.Ratings can be activated separately for each area, and the user must have permission to rate a given content-type.