Is there a way to systematically notice new comments as they appear? Ideally I'd like to receive them as individual e-mails with subject being equal to post title, for gmail threading magic to facilitate efficient skimming.

As it is, tree view makes it difficult to keep track of the conversation as it unfolds, it's even worse than on OB where there was no native way to subscribe (I use backtype for that purpose, a still buggy comment scanner). Maybe the simplest step for now is to allow flat view for discussion.