From Wikipedia - EMO (not to be confused with Goth)
The word has more recently been used to describe a subculture as a slang term, but still describes a music genre as well. The term emo as a music genre has become broader and broader with time, and now is loosely understood to mean "rock music with emotionally-based lyrics or effect." Bands included in the genre range from Bright Eyes to The Get Up Kids to Sunny Day Real Estate. The term is so loosely defined because its definition is still the subject of debate.[1][2][4] Emo now often refers to a person's fashion, personality, or both, as well as the music genre.