How do I subscribe to a specific Thread?

I'm loosing it ...:~
Can't remember how to subscribe to a thread I'd like to follow!!
(I am currently subscribed to 20 threads. Is this the limit?)
Tried the FAQ without much success..

Thanks Yvan

with the thread in question open, there's a "Thread tools" above the first post, top-right side. In that dropdown, there's a "Subscribe to thread" if you aren't subscribed, and that changes to the option to remove the subscription if you are subscribed.

Thanks Poundy!

:B

Cheers Yvan