This forum software works a little differently. Here's how to do it.
  1. From your your profile page, click the Edit link next to Subscribe/Unsubscribe settings (or just click here).
  2. Change the second option, "Do you want all replies to your favorite topics emailed to you?", to Yes.
  3. Mark the threads that you want to receive emails for as favorites by clicking the "Favorite Topic (toggle)" link near the bottom of any topic's page.