Here’s a simple block that allows you to add a Facebook Comments block right to your course. The block can be consistent throughout the site or can be setup as a new one for each course/page. A few other customization options allow you to curate comments, change the theme color and decide how many comments display.
The block was created by Ankit Agarwal of Moodle HQ. Check it out and download it from https://moodle.org/plugins/view.php?plugin=block_fbcomments
And if you’re seeking even more Facebook for your Moodle: