Crooked Timber had a quote about comments
that pretty much reflected my own experience, "The number of comments a post gets is not, in any way, analogous to the importance attached to the post by commenters. ... Comments are not a reflection of how much your audience cares about a topic. They are a reflection of how much they have to say on it."
Since I started this site I've been amazed at my inability to predict what kind of content people will comment on. When I think I've written something super interesting it will get no comments and then when I think I've written something super throw away, it will get fifteen. I don't think that's a good thing or bad thing, just a thing. I generally agree that the more out there a post is, the less easy it is to respond to and that probably causes people to abstain. I also think I'm going to go with something similar to the comment system Buzzfeed
has when I redesign this site (coming really soon). In addition to text comments, they now have "reactions" which you can choose from a pre-populated list (for them it's like, LOL, OMG, CUTE!, etc. ... Probably be a little different here.)