I've had to deactivate this plugin and go back to using disqus instead of Jetpack comments because whenever a user tries to leave a comment nothing happens. What I mean is that when they click to submit a comment, after login in, quite literally nothing happens - the comment isn't submitted, no refresh,.. nothing! The only way I can get it to work is by going into the admin panels discussion settings and deselecting must be logged in to comment. If this is activated comments wont post. Its the same problem no matter which service they registered with, Facebook, Twitter etc. I'm not sure if this is a conflict with the Jetpack plugin but I wanted to use your plugin to ensure a 'members only' commenting site.