there's a button at teh bottom of the thread (well, a line of four buttons)
1) Subscribe to thread
2) Email thread
3) Add thread to favorites
4) Print thread
*edit*
I believe what you are looking for is "Add thread to favorites" - you can click on "TODAY" up near the top of the window, on the right side, and go straight to it.
#1 emails the thread replies to you and such.
*edit2*
upon seeing Konichiwa's post, I realized he was right. click on "Today" up at the top.