If I reply to someone's discussion and a third party replies to my comment, the discussion creator sees that third party's reply, but I don't. (As far as I can tell.) I would expect a reply to one of my replies to show up on My Page.
Also, if I reply to someone who responded to one of my discussions, they only see my reply to them if they revisit the discussion. As far as I can tell, my replies to them don't appear on their My Page. It makes it difficult to actually have a discussion that way. :-)
To give an example along those lines - On the discussion that I started titled "What's your favorite name?" Jill replied on 8/1 that there is a Hezekiah in her husband's ancestry. On 9/3, Tina replied to Jill's post and asked what the surname is for Jill's Hezekiah. Tina's reply to Jill showed up on my My Page since I created the discussion, but not on Jill's My Page. So Jill wouldn't know that Tina asked her a question unless she (Jill) revisits the discussion.
Hopefully that's not too convoluted.
Maybe I'm just missing something. But, if not, is there a way that this can be changed?