esoTalk – Fat-free forum software

esoTalk is a free, open-source forum software package built with PHP and MySQL. It is designed to be:

• Fast. esoTalk's code was architectured to have little overhead and to be as efficient as possible.
• Simple. All of esoTalk's interfaces are designed around simplicity, ease-of-use, and speed.
• Powerful. Despite its simplicity, a large array of plugins, skins and languages are available to extend the functionality of esoTalk.

 https://github.com/madromas/esoTalk-v3