There's already a lot of discussion of what's lacking with Plone's OOTB commenting support and looming large among them is lack of notification. Many of the blogging and forum add-ons out there have notification solutions, but I wanted to stay OOTB if possible.
Enter RSS searches. As a site administrator I can keep abreast of the comments on my site by subscribing to a simple RSS feed so a search query on the comment content type and sorted by the creation date:
If I wanted to be notified of comments on a particular object, I can add that object's talkback path to the query and subscribe to the resulting feed:
It's even possible to build a search query that tracks the replies to a specific comment using the in_reply_to index and the comment's number:
Of course, this isn't hierarchical in the sense that replies to a reply won't appear in this query. That, however, could be fixed with a small change by making the in_reply_to index a KeywordIndex that indexed multiple comment number values.
It would also be tres cool to add these RSS feed links to the comments UI somewhere making it convenient to subscribe to the particular comment threads a user might be interested in.
Anyone want to sponsor this? :)
This combined with any of the many RSS to email web services out there would actually make quite a powerful poor-person's email notification system if you absolutely had to have email notification. I could even make the argument that RSS is a more appropriate channel for comment notification than email anyways. In the manner of confessions, I use rss2email.