What is the most efficient method to receive notification that your Thwack post has been answered?

i usually receive automatic email whenever any one comment on a question I post on thwack. I do not do anything more than posting the question

Yes per Ahmed, you should have received 2 emails now [if not, make sure 'Follow' over on the right is marked] 

Besides stalking your post, or politely bumping your post once every 2nd day so it appears briefly in the recent content.

But if it was super issue, then you would log a case I hope

As per above, you should automatically get emails when your posts are replied to, or when someone replies to a thread you have posted in. If you are not, I suggest checking your profile settings.

If I am interested in what responses a thread receives but don't want to post - I click on the Follow link in the top right corner and tick Email Watches. I'll then receive an email when someone replies to the thread.

This is all true. The one item that you might want to include;  If you want the notification that someone replied, go into you account preferences and turn on notofications and make sure the email you want the notification sent to is correct. Go to the down arrow of your profile avatar in the upper right corner.  Click on the down arrow and select preferences.  The settings are at the top of that page.