You have two options to avoid receiving a message for every post.
If you want to be notified on a daily basis, choose Daily Email Digest
If you want to be notified on a weekly basis, choose Weekly Email Digest
Whichever you choose will be the default setting for all your topics. You can change that setting for specific topics by clicking on topics
on the left side of your control panel, a handy feature if there are topics you need immediate notification for but your default is a digest. This will show a list of all the topics, organized by forum, that you are currently subscribed to. Here you can elect to unsubscribe, receive no notifications, and the e-mail notification options for each and every topic. You can select from 1 to all your topics at at time. There are little boxes to the right that you can put check marks in, and at the bottom is the option box of subscription and notification choices followed by a button that says selected
. That's the button you click on after you make your choice.