If you want to subscribed to a December, 2008 watch code thread, it's simple. Just a few posts down from your's is a December 2008 watch code thread. Simply click on the thread. Scroll down to the last post. Click Reply. In the Message Box, just type in "subscribing". Then click "submit reply". From then on, you should receive any replies posted in that thread. Meaning, if somebody posts a code on that thread, you'll get notice of it.
Hope that didn't sound too confusing.