I'VE SEARCHED, AND NOTHING CAME UP. IF THERE WAS A THREAD ABOUT THIS, I'M SORRY.
So anyway, we're all excited for the upcoming L4D DLC that's going to be released this Spring. Yesterday, IGN released a video regarding such anticipated DLC.
If anyone has already heard about this, then whatever. Discuss. Brag. Punch a baby. I don't care.
Anyway, as far as survival goes, it's pretty obvious to what it was going to be. Try to survive as long as you can.. There's the time that records how long you've been playing, your team's best time, and endless waves of hordes and special infected ready to tear you to pieces.
Being the only video released (not that I know of) about the Survival mode, it's still not informative enough to answer all the questions.