It's convenient to set up a comment system in Jekyll site with external social comment systems like Disqus or Duoshuo (多说). However, as you all know, Disqus was blocked in China and Duoshuo is going to shutdown. It's the time to rethink about the comment system (although I didn't get too many comments →_→), simple and controllable. And it becomes true with Firebase database.
Firebase Hosting is a developer focused static web hosting provider that is super fast, secure and reliable. You can quickly and easily deploy your static websites to a global content-delivery network (CDN) with a single command.