I explored this for my static website (hosted on github), Didn't fit my needs exactly. So I started building one in flask and mySQL recently: https://github.com/singhjaideep/flask_comment
I'm curious about why you have a static website hosted by someone else, but then host your own comments? Is there some advantage to keeping the comments separated from the content?
Actually I wanted something even more simpler. No usernames, avatars,emails,threading, none of that. I just wanted the simplest way to add comments, and to keep spammers out, that it. I feel isso is more useful for blogs that have a ton of comment interactions. FYI I agree that comments are not bigdata, I should have used sqlite as well..