I personally love the Yahoo! questions site where people ask the questions and the best smart ass answers wins. This time someone got it right to a T! Thank you for spreading the good word!

http://answers.yahoo.com/question/index?qid=20110603112533AASw2ft

Question:
What is 'emo' music ? ( as in the definition)?
I don't understand what emo music is I listen to techno, screamo, alternative rock, post hardcore and stuff like that a mixture, but I don't get what emo music is. If 'emo' stands for emotional then what is other music? Without emotion music sounds stupid, well in my opinion so what is the definition of emo music this has been bothering me for ages thank you :) x

Best Answer:
Emo comes from Emotional Hardcore, a genre created in the 80s in D.C. by bands like Rites of Spring. It marked a move from traditional hardcore which tended to be more political and less melodic in nature to this new thing which had more expression and more of a darker introspective tone and obviously was more melodic. It has sort of taken on new meaning as a poppy punk type genre with a specific look and demeanor but don't bother with that as it isn't the good stuff.

Gray Matter, Beefeater, Fire Party, Dag Nasty, Rites of Spring, Embrace are all quality bands of the Emo genre and some of the folks in Embrace and RoS went on to form Fugazi.

If you are looking for more modern stuff I would stick with Mineral, Jawbreaker and Sunny Day Real Estate and stuff like that.