[svenrufus]

I think this is what you are after.

If you click on 'your posts' icon at the top of the page, there is displayed all the threads you are subscribed to. If you tick the box next to the ones you don't want to be notified about, then at the bottom of the page there is a drop down menu that gives options like 'Delete Subscription' or 'No email notification'
I've never used it, but I think that will do what you want to do.
cheers
Sven