As it is, you only see new comments if you scroll past the post again (and your client has refreshed it) or if you open it directly. If your client hasn’t updated the comment count or if you refresh your feed and the post falls off, you’ll never see it anyway.

A “Watch” feature would solve this better. If you watch a post, you get aggregated notifications for edits and comments on the post. If you watch a comment, you get aggregated notifications for replies to it or any of its children.

By aggregated notifications, I mean that you’d get one notification that said “The post you watched has been edited; 5 new comments” rather than a notification for each new comment.

Then, in addition to exposing a “Watch” action on posts and comments, clients could also enable users to automatically hide posts that are watched, either by marking them as hidden or by hiding watched posts without updates.

If the latter approach were taken, notifications might not even be necessary - the post could just get added back into the user’s feed when changes were made. It would result in a similar experience to forums, where new activity in a topic would bump it to the front, but it would only impact the people who were watching it.

You can kinda get that behavior by sorting your feed by Active, but this could be used with other sorting methods.