1. There's a dark gray taskbar near the top of each page. You should see User CP in it. Click on that.
2. On the left of the page that appears is a sidebar titled Your Control Panel. Look for a subheading called Settings & Options in that sidebar.
3. Under Settings & Options is a link called Edit Options. Click on that.
4. The first big box is Login & Privacy. You're not interested in this one today. Go down one more.
5. The next big box is Messaging & Notification. This has the sub-box where you get to choose how Emails are sent to you. Find Default Thread Subscription Mode.
6. In this box, choose Daily email ntification from the drop down menu and you're set. Any thread you post in or any thread you create automatically "enrolls" you as a subscriber to that thread by default. Whenever there is activity in that thread, you'll get an Email notifier sent to the Email addy you used to register with the website. Activity can be an actual reply or a vote on a poll if the thread has a poll associated with it.
7. Actually, there is one more thing to do. Scroll all the way down to the bottom of the page and then click Save Changes and now you're set!