I've been making a conscious effort to reply to posts I find interesting, even if I'm just adding a sentence or two and not the most engaging of content. At least it helps get things started, I think.
My problem is that I'm experiencing a bug wherein I don't get notifications when people reply to me unless they @ me, so I can only see if somebody has by going back and looking at my own comments through my profile. I assume that'll eventually be fixed, but if others are experiencing the same bug, that will be a huge drag on discussion.