So you see that there is a common theme: both actually evoke a response from your viewers: either through recollect or through controversy. Obviously each post cannot do one of these two things, but you can try to throw something in each post that will evoke some kind of response from your viewer.
As mentioned previously, a question is one thing, but perhaps also some call to action. For example, if there is an upcoming event (even if it is unrelated to the story), maybe mentioning that at the very end of the article and asking them to rsvp through the comments will give more incentive to the viewers to post, and they may subsequently comment on the article itself since they are being asked to comment anyway.
Motivation for Entrepreneurs