I feel that if in general you want the authors to engage, I would ask the audience to post the comments on the author's blog (for those blogs that support comme

I feel that if in general you want the authors to engage, I would ask the audience to post the comments on the author's blog (for those blogs that support comments). In this specific case it's a bit trickier because you want authors to post their content, and this may or may not be in line with your goal, depending on whether you e.g. prioritise build another community (social network?) of people interested in blogging or reducing reliance on <big centralised websites>. I would prefer reducing the comment fragmentation in this kind of a context.