HashOver looks like a pretty nice commenting system. HashOver ~ Free and Open Source PHP Comment System | http://tildehash.com/?page=hashover I just glanced at it, but it's the only viable 3rd party I've seen. Example implementation: Implementing the HashOver open source commenting system within Pelican | http://moparx.com/2014/03/implementing-the-hashover-open-source-commenting-system-within-pelican/
