Hello there!
I looked around the mod section and I didn't see anything like this so I thought I would post it here.
I think it would be great to know how I had notifications set when I was looking at a board or a thread. Right now, the only ways I can discern my notification status is to either go into my profile to see if I'm signed up for notifications on that board/thread or I have to click on the notify button and based on what it tells me I'll know if I am subscribed or not.
What I am proposing is having an active display setting so you always know if you are or are not subscribed to a board/thread. Depending on if you are subscribed or not, the notification button would look different. A couple of examples are listed below.
Please let me know if you have any questions or need any clarifications.
Cheers.
Standard Icon as it is today:

Possible "on" notification, it changes color:

Or just say, "notify on":

Or "notify off":
How would that work in the default theme, which uses text instead of images?
Could be like how I have that second set of buttons, but instead just using text to indicate whether notifications are on or off for that thread. :)
"Notifications On"
"Notifications Off"
Or something like that...