This is one of the AB "services" that fell by the wayside when "new" AB was introduced, and has not (yet) been reinstated by AB.
Like lots of things they keep promising to reinstate but never do.
Ah,but can you subscribe to your own question just to receive notification of replies?
It was much easier before, when if you got a reply you got an advisory email.
The subscribing email is really so you can be notified when there is new answer to a thread you have already left an answer on.
Just log into SUBSCRIBE TO QUESTION and you will receive a notification by e-mail to your own question or to one posted by someone else. 'Simple' as the meercat would say!