I've found that if someone replies to a suggestion I made by hitting the reply button at the bottom of a thread, I won't get a notification. I will get one if they hit the reply button next to my comment, however. Maybe I've misunderstood how this works, but I often find myself manually trawling through my activity list to see if people still need help.
I sometimes forget too, and wonder if I'm not getting a reply to the suggestion I spent an hour on because people aren't getting notifications. The only thing I've thought to do is to edit my comment and @ them.
So I have two questions:
Am I talking out of my arse?
Is there a way to change a general reply to a personal one after the fact?
I'm pretty sure the default notifications preference when you post in a topic is "Tracking" which will notify you if you are mentioned or if someone replies to your post in a topic. You can change this default in User_Preferences_Notifications (or per topic, using the dropdown on the topics page shown after the last post) to "Watching" which will notify you of every post in the topic.
As it stands, the user would have to know or be prompted to make their own change on this.
You can change the topic from Tracking to Watching, and I think you'll get notified on replies to the topic in addition to replies to your post within the topic
This one really messed with me too. I thought that "Tracking" was the highest level of observation and was constantly wondering why I was missing notifications.
I finally fixed that a couple of years ago, and I also changed the way I use the forum.
I nearly always use the keyboard to navigate through topics and reply.
j == move down one post.
k == move up one post.
r == reply to the selected post.
R == reply to the Topic.
q == quote the selected post (or selected text).
Use ⌘? in the forum to show the help overlay.
Here's what a selected post in a topic looks like:
Note too that when replying to an individual the editor will show their avatar image at the upper left – unless you reply to the owner of the topic (Original Poster); in that case there will be no avatar (which is bad UI in my opinion).
Using this technique consistently has helped me make fewer mistakes and therefore made my Discourse Life a bit smoother.