a commenting server similar to Disqus.

Isso – Ich schrei sonst – is a lightweight commenting server written in Python and JavaScript. It aims to be a drop-in replacement for Disqus.

Isso @ GitHub.

yet another commenting system. Heex was designed from the ground up to be easily installed and used to get your comment section seamlessly added to your app or website.

Heex @ GitHub.

Using GitHub issues as a comment plugin.
Octomments @ GitHub

A lightweight comments widget built on GitHub issues. Use GitHub issues for blog comments, wiki pages and more!

Open source & privacy friendly disqus alternate

a commenting server similar to Disqus

A sweet ass commenting interface component.