An internet search will give you most of those acronyms as well as explantions. And Wikipedia is always a valuable source.

SSC of course, is Safe Sane Consentual
RACK is Risk Aware Consentual Kink
WIITWD is What It Is That We Do

PRICK was originally just made up so that someone could say, I prefer PRICK. Personal Responsibility Informed Consentual Kink. Pretty convoluted eh?