real-time comments

 real-time comments  are the display of comments on a view of a post (typically on its permalink) as they are received by the post (presumably via webmention), without needing any explicit user reloading, refreshing, or any other tapping/clicking etc.

Real-time comments are one of several real-time interactions.

Aaron Parecki
uses p3k on aaronparecki.com post permalinks to show real-time comments since 2013-10-13.
 * http://aaronparecki.com/articles/2013/10/13/1/realtime-indieweb-comments

Pelle Wessman
Pelle Wessman uses A WebMention Endpoint on VoxPelli.com post permalinks to show real-time comments since 2014-12-07.

Silo Examples
Real-time comments are a silo innovation.

Facebook
Facebook was perhaps the first silo to implement real-time comments since 2012(?) at least, on both post permalinks, and sometimes on posts in a stream or in a collection.

Twitter
Twitter, as of their mid-2014 front-end redesign, now supports (sometimes) showing real-time comments on tweet permalinks: