Click on Forums, not My Forums, but all. Find the forum you wish to subscribe to, click on that Forum to open it, and in the blue bar where the name of the Forum is, you will find a listing on the right hand side, that says forum tools. Click on this, and one of the listings is "Subscribe to this Forum".
Hope that makes sense.
Last edited by kwblake; 12-22-2013 at 10:03 AM.