This is one of my own frustrations with HN. The issue isn't quite as bad as on other discussion sites, but generally, conversations ... fade quickly. I'd like to see
some kind of mechanism which works against this tendency.
That said, notifications of themselves ... probably aren't that. Though there might be ways to tweak the mechanic to induce this.
Google+ had a Notifications dynamic that seemed to work well in this effect, though it was somewhat specific to how that site was structured:
- Notifications were for specific discussions.
- Disucssions were hosted by a specific user.
- The Notification went out to all (recent-ish) participants in the discussion.
- Discussion hosts could moderate the thread. This was a two-edged sword, but tended to reduce spam and flamebait when used well.
- The Notifications Pane itself wasn't merely a "something happened" nag, but a site element where new comments could be directly responded to.
- Discussion threads were flat, with most-recent comments appearing at the bottom of the thread. I'd at first missed the threaded style, but came to appreciate a flat disucssion which didn't descend into long separated exchanges (frequently flamefests), and for which each subsequent response was an equal contribution to the thread.
- Total thread length was limited to 500 replies.
It's not the same as a topical or open-discussion formum, as with HN. But as a conversation-fostering platform given the right host and participants it could and often did work quite well.
A result was conversations which evolved naturally over days and weeks, sometimes months and years. Conversations didn't simply die.