Phorum : Phorum was the original PHP and MySQL based Open Source forum software.
Phorum

Phorum Screenshot
Overview
Phorum was the original PHP and MySQL based Open Source forum software. Phorum's developers pride themselves on creating message board software that is designed to meet different needs of different web sites while not sacrificing performance or features.

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Features

Performance

The group of developers of Phorum had very different needs. The end result is a versatile product that can serve anyone's needs.