The default behaviour of comments in an Elgg system is similar to that of standard blogging software, in that comment notifications only go to the post’s original author.
So, if Alice uploads a file and Bob comments on it, Alice would receive a notification. If Charlie comments on it as well, only Alice would receive the notification. In a modern social network, this artificially stifles conversation.
So, I wrote a very quick plugin which modifies the default notification behaviour slightly…
Now, with this plugin activated, if Charlie leaves a comment, both Alice and Bob will receive a notification.
Simple, but quite handy.