Some additional repos to consider:
Comment-System-Series — This is the comment system I am building on YouTube.
loudvoice-comment-system-wordpress — LoudVoice replaces the basic WordPress comments by a powerful comment system that includes logging in with 35+ social networks, spam filters and more.
bp-notify-post-author-on-blog-comment — Notify the blog post author on blog comment using BuddyPress notification system
Once a week...... I send out a list of most interesting PHP libraries and apps.
Want to get it?