It's just like a zap, except "Fuck you" instead of "Thank you." You basically pay the system to un-promote their content, then your sats go into the general rewards pool. It honestly works well most of the time, but can be unbalanced (as here) when someone really hates a dude like and pays to make his posts invisible.

Stacker News is one of, if not the, best place for news and in-depth discussion about substantial things happening with the network. did some good work there.