From OpenBRR

Member Features

User profiles

User ranking

User Control Panel

Private Messaging

Member expertise

Email Subscriptions

Thread Tracking

Forum search

Forum Control

Unlimited Forums and Categories

Read only Forums

Password-protected Forums

Forum Announcements

Sticky Threads

User and Group permission management

Word censoring

Administrative Control

Multiple Administrators

Ban Management

IP tracking

Flood Control

Anti-spam

Mass emailing

Customizable Markup

Topic splitting

Pruning

Reserved Usernames

Custom Titles

Language files

Payment System

Board Features

Member lists

Calendar

Board Statistics

Low-Fi Version

Printable versions

RSS Feeds

Help system

Interface Features

Flat

Threaded

Avatars

Signatures

Templates

Skins

User Customizeble Display

Messages

Quote

Code display

Image posting

URL linking

Emoticons

Spellchecking

WYSIWYG

Quick reply

Post Preview

Post Editing

Polls

Attachments

Guest posting