Oh wow that's huge news! I had no idea.
As far as interaction goes, I've noticed that A LOT of webcomics hosting their own sites almost never have comments. The exceptions are sites that appear to be a personal site but are in-fact linked within a webcomic farm.
Some of the best webcomics I've ever seen have a comment section that is just a barren desolate wasteland. Perhaps re-posting to a facebook page would generate the interaction you desire, where people are already logged in when they see your page so they don't have to 'log in' just to type a comment?
Before going with Discus I considered just allowing anyone to annonymously post, but that would just get swamped with hundreds of robot spams eventually.
I personally don't get much interaction on my webcomic, but I always make sure to immediately respond as fast as possible to any comments.
Hope this helps!