No no no...you all have it wrong.
You see, S&F stands for:
Stand & Fart!
So as to release the built up pressure from reading the post!
That's the only reason I ever use it...and according to me, is the definition.
Or maybe its:
Starsky & Futch
Schooled & Fooled
Stopped & Farted
I might be taking it too far....
*S&F*
(with no actual star in this board)
By the way, use this:
ATS Search for all your FAQ's.
Or click on the Search box above the thread topic logo, towards the right side of the screen.
Maybe this will help because there are tons of helpful threads on this site.

edit on 25-9-2011 by havok because: Added. Link or two