You may notice some new features to the forums =)
Here's a brief list:
* Thread tagging
* Search cloud / tag cloud
* Thread prefixes
* Reciprocal friendships between users
* Public visitor messaging on profile pages with 'conversation' feature
* User picture galleries with user comment facility
* User-created social groups with invite only and moderated membership options
* Extended member profile pages
* Customizable member profile pages with admin-controlled styling abilities
* Inline editing of custom user profile fields
* Lightbox viewer for attached images
* Viewable and comparable history maintained for post edits
* User change history
* Social bookmarking integration