I've seen these cropping up on sites recently, and a few Facebook friends have started doing it - basically, if you're posting something that is distressing or disturbing, you'd lead off with TW: Suicide (or rape, or self-harm, or whatever), like a spoiler warning. Is this a good thing, to look out for people? Or a bit much? It sort of struck me after Bam's thread on suicide yesterday.
I guess DiS could have specific ones too (Feminism, arse-wiping, moker*).
*Love you really mokes.