If you want to automatically receive an email when someone makes a post to a topic of interest to you:
1. Go to your Profile by clicking your name in the upper left of the screen (after "Welcome".)
2. Edit. Click the Edit button, upper right.
3. Scroll down to Favorite Notification. Make sure Activate is checked. You should only have to do this once.
4. Scroll down and Update Profile.
5. When you open up a topic, at the top, just below the topic's title, click "Add this topic to your favorites"