If you wish to be notified via e-mail of new posts or topics to this forum, set your forum options as described below:

1. Select a forum (options need to be set for *each* forum)
2. At the bottom of the forum list of topics, you can see the [Options] button
    
3. Click [Options] to see the Forum Options items
4. You may set your Sort, Date Filter and Topic Filter options as you wish (but usually I leave them as default)
   
5. In the Send E-mail option, select:
   1. "never" - default, no email is sent to you on new post or topic
   2. "when new topics are posted in this forum" - email sent to you only when a new topic is made
   3. "when new posts are posted in this forum" - email sent to you when a new post to an existing topic or new topic is made
       
6. Click "Apply" to save your changes.
7. You should now receive an email whenever someone makes a new post or topic.

Here's a more visual look at how you can set the options of individual forum to notify you when there's a new post or thread.

If the Forum Options dialog box shown below is not visible in the forum you wish to track,
click on the Options button to open the dialog box.

The Forum Options Dialog Form

Below is a blown-up image of the Forum Options only

In the Forum Options dialog box (at the bottom of the image above), you can set the options to Send E-mail to suit your own individual preferences

1. Never - This option will mean the forum will not notify you of any new topic or post unless you set it at individual topic level
    
2. When new topics are posted in this forum - This option sends you an email when someone post a new topic. Only new topics would trigger an email to you. Replies to an existing topic would not.
    
3. When new posts are posted in this forum - This option will send an email to you whenever someone makes a post to the forum, whether it's a new topic or replies to existing topics.

Note: The 3rd option is what I normally set for forums which I take an active interest in.