Yeah, I thought for a minute- dollars, pounds, Euros… 
Go to click on your avatar > click on your name > select the preferences tab > select Notifications from the column on the left > select as desired
Except that Discourse will also put any thread you’ve read for a while into Tracking; so there’s no way, without opening the thread, to tell a thread that’s in Tracking because you posted in it from one that’s in Tracking because you only read it.
You can individually set the only-read threads back to Normal. But there isn’t any option in preferences to not have threads you’ve only read not set to tracking – the best you can do is to raise the time you spend reading the thread before that happens to ten minutes.
It makes no sense at all to me, and I find it really annoying, that I can tell preferences to leave a thread as normal if I’ve posted in it, but can’t tell preferences to leave a thread as normal if I’ve only read it.
Yes, there is. The first option on the list is ‘never’. Just scroll up the list of options.
You’re right; and I didn’t see that. I clicked on the menu and got offered “five minutes”, “ten minutes”, and one other time less than ten minutes, I forget which. I didn’t see the nearly-invisible scroll bar, and assumed that was the whole list.
Thanks! That was making me grumpy; and now it won’t.