Subscription emails
 

I subscribe to many threads and I have all of them set to instantly email me when there is a new post.
Most send one email when there is a new response to that thread and then no more until I log into the thread again. However, there are some thread subscriptions that I continue to get instant email notifications regardless of whether I visit Bike Forums or not.

What's the difference in settings? I can't see anyway of how to change it.

-Bob