SMF is a very versatile forum software. It has many features, including the following:

General

• Uses PHP, and a database system: MySQL, PostgreSQL or SQLite.
• Comprehensive template system.
• Advanced permission and user management.
• Supports multiple languages at once.
• Open and well-documented source code.
• Tracking of new and old unread topics, not just from your last visit.
• Designed for optimal performance and scalability.
• Multi-media output: XHTML, XML, RSS, WAP
• Multi-language support from a large community.
• Package manager that automatically installs or uninstalls mods (also known as packages.)
• Search:
  • Search the entire forum, a category/board or within a topic.
  • Search within your personal messages.

Security

• All actions seamlessly require a session based authorization code.
• Administrative actions require the user's password (and do not rely solely on cookies.)
• Major actions are time and IP locked, preventing 'hammering'.
• The number of login attempts from a certain IP can be limited and time locked.

Forum Settings

• Ability to display page creation time and query count per page.
• Put a board into maintenance mode, allowing only admins to login.
• Word censoring, either full word or partial.
• Ability to break up long words.

Boards and Categories

• Group boards into collapsible categories.
• Set categories as non-collapsible.
• Reorder boards within categories, or reorder categories.
• Create child boards under other boards. (sub boards)
• Assign moderators to boards.
• Allow certain membergroups to access a board, including guests only.
• Configure permissions for each membergroup on the board level.
• Ability to indicate new posts to child boards but nothing new in parent.

Member Registration

• Require registration before forum entrance.
• Require a user to agree to terms before they register.
• Disable member registration completely (allowing only moderators to register people).
• Require email authentication by sending an authentication link.
• Require a moderator to approve registration.
• Register new members from the admin center.

Member Navigation and Authentication

• Several security checks during navigation.
• Password reminder option, by email with confirmation. (doesn't automatically reset your password.)
• Both cookie and session based authentication (works without cookies.)
• Cookies can be set local to a path, global to all subdomains, or normally.
• Adjustable expiration time for authentication cookies.

Member Tracking and Tracing

• Sortable and searchable public memberlist (accessible by a permission.)
• Powerful sortable and searchable admin memberlist.
• Show all (error) messages and IPs made by a member. (track user)
• Show all (error) messages from an IP address or range. (track IP)
• See who's doing what (accessible by permission.)

Statistics

• Several board statistics (accessible by permission.)
• Tracking of member's online time in seconds.
• Tracking of topics, messages, new members, and hits per day.
• Individual member statistics accessible from their profile.

News and Announcements

• Send a Newsletter from the admin center, or post any topic as an Announcement, using "Attachments and other options"
• Member option to disable receiving announcements (and Admin override of this option).
• Email or private message your members by membergroup.
• Show a news ticker or news fader.

Communication

• Ability to choose sendmail or SMTP (with or without authentication.)
• Ability to send a topic to a friend.
• Ability to view a "printer friendly" version of topics.

Membergroups

• Create membergroups to group members on permissions, access rights, and/or appearance.
• Assign several membergroups to a single member, with one membergroup as the primary group.
• Define membergroups that are auto-assigned based on the amount of posts a user has.
• Determine the maximum number of personal messages a membergroup is allowed to have by group.
• Assign graphical symbol(s) to a membergroup - by primary group.
• Determine which membergroups are allowed to access a board.

Banning

• Ban members based on their username, email address, IP address or hostname.
• Support of wildcards for email address, IP address, and hostname.
• Include a ban reason (viewable for the banned user).
• Include a ban note (only viewable by the admins).
• Chose between full ban, 'no post' ban, or registration ban.
• Include an expiration time for bans.

External integration

• Integrate parts of forum software into existing website using SSI or PHP.
• Recent topics or posts.
• Recent news posts in a board.
• Recent polls.

Export forum data using XML/RSS

• Latest members.
• News.
• Recent posts.

Wireless access

• Support for WAP, WAP2 and I-mode protocols.
• Browse through boards/topics/messages with reduced page size.
• Ability to login and logout (not with WAP 1.)
• Ability to see new topics/boards with new replies.
• Ability to jump to first unread reply.
• Ability to post new messages (not with WAP 1.)

Theming and Templating

• Ability to allow or disallow your users to select their own theme.
• Ability to reset all of your members to a certain theme.
• Ability to install a new theme via your administration center.
• Default templates are XHTML 1.0 Transitional and CSS 2.0 compliant.
• Admin can add smileys and smiley sets.
• Members can choose which smiley set they wish to use (or none.)
• Themes can be installed by way of the "latest and greatest themes" panel.
• SSI can have and show layers and the like from the template system.

Posting Features

• Spell Check.
• Quick Reply
  • Members can disable it or collapse it.
  • Can be used with "Quote".
  • Also contains "Spell Check".
• Vast number of "bulletin board codes" to use (including rtl, acronym, and others.)
• Optional editing grace period before a post is shown as modified.
• Insert Quote feature on posting screen to quickly quote previous replies.

Polls

• Can be added or removed to existing topics.
• Ability to set expiration date.
• Ability to hide results till expiration of poll.
• Ability to hide results until after people have voted.
• Ability to determine how many votes a user may cast.
• Polls can have up to 256 options.

Attachments

• Allowed on a per member group or board basis.
• The filename is hashed to increase the security (so you can upload .php files, etc.)
• Optional restriction on what filetypes may be uploaded.
• Ability to restrict such that only registered members can view them (disables hotlinking, mostly.)
• Images can be embedded into posts.

Calendar Support

• Shows Birthdays, Events and Holidays.
• Display calendar information on board index.
• Link an existing topic to the calendar.
• Allow only certain members/groups post events.
• Event poster can edit event.
• Events can span multiple days.

Moderation Tools

• Ability to lock and unlock a topic.
• Topics which are locked by an administrator can not unlocked by anyone else.
• Ability to allow members to use moderation on just topics they posted.
• Report to moderator" link.
• Delete or modify posts.
• Ability to Merge/Split topics.
• Move or delete topics.
• Sticky or unsticky topics.
• Recycle bin/board for all deleted topics and posts.
• Moderation log which shows moderation activity and disallows log removal outside of 1 day.
• AJAX editing:
  • Edit a post without page reloads.
  • Double click to edit topic subjects on message index.

User Profiles and User Options

• Ability to hide your email address from the public.
• Select their favorite theme among the activated forum themes.
• Select their smiley set from the ones available.
• Email notification
  • New topics per board.
  • Single topics.
  • Private messages.
• Login with 'invisible' mode.
• Options to hide other members' avatars and signatures.
• Ability to download and resize uploaded avatars.
• Personal text, avatar, signature, and all the niceties of forums can be used and are kept up to date in all your posts.

User Resources

• Icons for topics you've posted to.
• Show new replies to your posts.
• Collapsible 'Additional Options' on post screen.
• Ability to view most recent messages.
• List all topics that have new replies since your last visit.
• See who is browsing the same boards or topics as you.
• Topics that span multiple pages have the page numbers listed as well as an "all" link.

Other features

• Several forum statistics
• List of users online.
• The menu bar.
• News.
• Search.
• Login/logout.
• Today's events/birthdays/holidays.