Perhaps this exists but I have found it not . . . . .
I would like to enable alerts of updated comments to a post to prior posters. For example, if Post 99 is commented on by Posters Aloysius, Beatrice and Carlyle, I would like each poster to be alerted, similarly to the way the weblog owner is, as new comments are added.
So when Deirdre adds her 2 cents, Aloysius, Beatrice, and Carlyle can come back and add theirs, and likewise when Elihu adds his . . . .