This is a great question. Do you know the answer? Do you know how find out? It depends on the service you use. I use feedblitz. This is how you find it in feedblitz.
1) Log in to your account at FeedBlitz and choose your list(s) from the site navigation.
2) For each list:
a. Click the orange settings button upper right
b. In the Subscriber “Interactions and Notifications” section, update your open and click through settings as necessary.
c. While you’re in there, see if there’s anything else you’d like to change!
The reason why I use a mail service is I like the control I have over the way my content is delivered. The downside is the cost associated. That is why it is important to only pay for the people who are opening your newsletter. If they are not opening it then stop sending it. I hope that they will wonder what happen and visit my site. I intend to send out a mailing to let my fans know what I am going to do.