PunBB is a fast and lightweight PHP-powered discussion board. Its primary goals are to be faster, smaller and less graphically intensive as compared to other discussion boards. PunBB has fewer features than many other discussion boards, but is generally faster and outputs smaller, semantically correct XHTML-compliant pages.
Extension system based on hooking technique. One click extension installation, no need to modify forum's code anymore.
Full UTF-8 support.
More customizable styles, templating system.
New layout: markup, CSS, language files updated, markup helper functions added.
URL rewriting schemes, nice URLs built-in.
Split/merge topics functionality.
Multiple groups for moderators allowed.
Searches are now case-insensitive, extern.php improved, more global, per-group and per-user options added.
Certain "bad" characters are silently stripped out from the text input.
Got rid of extras folder, README added.
Hotfix system based on extension system for quick bugfixes.