vBulletin is a powerful, scalable and fully customizable forums package for your web site.

It has been written using the Web's quickest-growing scripting language; PHP, and is complemented with a highly efficient and ultra fast back-end database engine built using MySQL.

vBulletin is the ideal community solution for all medium-to-large sites.

Key features include:
- Fast and efficient database back end
- Template driven interface
- Powerful search engine
- Language system
- User profiles
- Extensive admin control panel
- Unlimited forums/posts
- Email notification
- Support for COPPA
General Forum Features:

Threads
- Thread display options - sort by, sort order, from date
- Thread and forum subscription (notification by email optional)
- Thread preview on mouse-over (optional, via Admin CP)
- Active Users viewing thread shown
- New Post Indicator
- Printer Friendly versions on threads
- Admin tools for Threads - edit/delete/move/lock/Make sticky/ etc
- Email page to a friend option
- Similar Threads displayed on all thread views
Posts
- Linear, Threaded, Hybrid display views available
- Supports BB Code in posts
- Supports HTML in post
- Smilies
- Avatars
- Optional WYSIWYG or standard editors for posts and Private Messages
- Attachment images (.gif,.jpg, etc) are no longer in the database (optional, via Admin CP)
- Quick reply box (with optional "forced" click on post to quote)
- Preview post option
- Post rating
- User reputation
- Polls
- Post Reporting - report posts to moderators
- User post count
- Admin tools for Posts - edit/delete/move/ etc
- Preview safe attachments
Members
- Member List
- Member Search
- User Style picker
- Private Messaging
- Buddy list
- Member Birthdays shown on Forum home
Calendar Features
- Supports multiple private and public calendars
- Viewable public and private events (adminCP option)
- Weekly, monthly and yearly views
- Jump to Today option
- Add single, ranged or recurring events
- Add all day events
- Option to show calendar event on forum home page (adminCP option)
- Show events to specific usergroups (adminCP option)
- Calendar Moderation
- Private events reminder
- Ability to add custom fields