Femdom=Female domination, where a woman is the dominant of a relationship rather than a male or an 'equal' relationship.
BDSM=Bondage and Discipline (BD), Dominance and Submission (DS), Sadism and Masochism (SM). Basically, someone who is into a bondage, or dominant/submissive lifestyle, the term is an acronym for the above words.
Smut=Is usually a catch all term for sexually focused or charged writing. IE: If a story is mostly about sex rather than story, it might be called a smut focused story.