If you host your source on GitHub, you should definitely check out Gitter. It's free for public repos and the integration is great; you get Markdown, integrations, IRC bridge, etc. Check for example the Marionette community to get a feeling of it: https://gitter.im/marionettejs/backbone.marionette. Disclaimer: I work at Gitter, feel free to ping me at https://gitter.im/malditogeek