Forum and thread types
The basic structure of a forum is a container for threads, those being a collection of posts, but from version 2.2 onwards, XenForo allows that model to be extended to support a variety of different behaviours.
This is the default, traditional thread type, used for general, unstructured conversation.
Discussion threads are generally shown with the original post first, and subsequent replies are shown sequentially afterwards. If a forum is set to display 20 posts per page, the second page of the thread will show the 21st post at the top.
Polls are a special type of discussion thread that also contain a poll - a multiple-choice question posed by the thread creator upon which other users may vote to express their choice.
A discussion forum is the standard forum type. It acts as a container for discussion threads and will generally show threads ordered by the date of their last reply, with the most recent shown first.
Filters are available to narrow down the list of threads shown, such as to show only those threads that have received no responses, or those within a particular date range, etc.
Mixed type forums
A mixed type forum is essentially a regular discussion forum that can also host other thread types. Support for article and question thread types may be added to discussion forums, which turns them into mixed-type forums.
To create a mixed-type forum, create or edit a regular discussion forum in the Admin control panel through the Node editor, and check the thread types you want to allow in the Allowed thread types section.
Some thread types may not be contained in a mixed-type forum at all, suggestions being one of those types.
Sometimes, threads are less about discussion and more about imparting knowledge. In these cases, article threads allow the first post in a thread to be afforded special treatment.
The first post in an article thread has extended limits on the number of embedded media items and attachments, has a greater character limit to allow very long textual content to be posted, and has different styling applied to make it appear distinct from subsequent posts in the thread.
Subsequent posts made to an article thread are considered to be comments on the article. At the point that the comments extend beyond a single page, a compressed version of the article will be shown at the top of each page, rather than being shown only at the top of the first page as would be the case with a discussion thread.
Dedicated article forums offer specific article-related display options for thread listings.
Preview display style
In preview mode, article previews are displayed in a masonry-style layout with a large 'cover' image and a snippet of the article text, instead of the basic thread listing style normally seen with discussion forums.
The 'cover' image is automatically extracted from the article text, using either the first attached image embedded within the article using the
[ATTACH] BB code tag, or otherwise the first linked image using the BB code
In both cases, a cover image may be specified for the article that is not shown within the article body by specifying a zero width and height for the image in the BB code tag.
Expanded display style
The expanded mode is intended to replicate the layout of blog-style pages, where full articles are displayed on a single page, ordered chronologically.
Clicking on any of the articles will take the viewer through to the article's own page, on which comments may be posted.
When a thread author is seeking an answer to a specific question they may post a question thread. The first post is the question, and will be displayed at the top of each page of the thread above all other replies.
Replies to the thread are considered to be answers to the question, any of which may be a possible solution.
Question threads are considered to be unsolved until one answer is selected as the solution. This can be done either by the thread author, if they have permission to do so, otherwise a solution may be selected by a forum moderator or administrator.
After a solution has been selected, the post selected as the solution will be displayed at the top of each page along with the question, and the thread will show as solved in its parent forum.
A question forum has a similar appearance to a discussion forum, but includes controls at the top of the thread listing to allow easy filtering of the questions.
Common filters include Unsolved questions, Your questions and Your answers.
Questions with a solution are shown with an icon to distinguish them from unsolved questions.
Suggestion threads are useful when you want to solicit feedback from your community in a structured fashion.
The first post of a suggestion thread is considered to be the suggestion, and controls are available to allow users with appropriate permissions to vote the suggestion up or down depending upon how they feel about it.
The vote score for a suggestion will determine its position within its parent forum, with suggestions having a higher vote score appearing further up the list than those with a lower vote score.
Suggestion threads may only be posted within dedicated suggestion forums, as the behaviour of the suggestion forum in ordering the contained suggestions is crucial to the functionality of the suggestion thread type.
Suggestion threads are shown ordered with those having a higher vote score before those with a lower score.
Filter controls are available to allow the list of threads to quickly be filtered down to popular or new solutions, along with options to show only the visitor's own suggestions or vote.
Thread type tools
Additional attention must be paid to threads when operations are performed upon them that would move them from one forum to another.
For example, moving a discussion thread into a suggestion forum (which can contain only suggestion threads) will automatically convert the thread type from discussion to suggestion, and moving a suggestion thread into a discussion forum will convert it to a plain discussion, which will cause all votes cast for that suggestion to be lost.
Moving a discussion, article or question thread out of a dedicated discussion, article or question forum into a mixed-type forum will allow the thread type to remain, though of course it will lose the forum-specific behaviours it had when it belonged to a type-specific forum.
Suggestion threads may only be moved into suggestion forums if the special properties of suggestion threads are to be retained.
These notes for moving threads also apply to other operations that may effectively move threads from one forum to another, such as merging, copying and spam cleaning.