* Add ability to (un)subscribe from comment threads on Forums and Photos.
* Creating a forum post, replying to a post or adding a comment to a photo
automatically subscribes you to be notified when somebody else adds a
comment to the thing later.
* At the top of each comment thread is a link to disable or re-enable your
subscription. You can join a subscription without even needing to comment.
If you click to disable notifications, they stay disabled even if you
add another comment later.
Noah