The drop down has three values:

Do not subscribe

No email notification

Immediate notification of new posts by email

I suggest a new option

Immediate notification of new posts to your posts only by email

Sometimes I am not concerned about what others might be posting.

When someone is responding to my post, then I want to know.

For example:

Joe DBA creates thread "What do I do now?"

I reply to his thread with my suggestion.

Now 10 other people also reply to his thread.

Finally Joe replies directly on my post.

I would like to only get an email on joe replying to my post. I don't really want to know 10 other people added their suggestions to his question.

Often when that happens I remove my subscription to that thread.