Emo = Emotional Hardcore
Contrary to popular belief,
Emo is not about being depressed or cutting,
it's not short for emotional,
it has nothing to do with teenage posers who follow the trend of pretending to be bisexual, depressed, and wearing all black.
It's not a fashion.
The fashion that's commonly referred to as "emo fashion",
is actually called "scene".
And MCR and Fallout Boy are NOT emo.
In actuality, It's a branch off of hardcore punk that started in the mid 80s with the punk band, Rites of Spring.
They hated the glorified violence and restrained music that infected the D.C. hardcore scene,
and took hardcore to a greater level of experimentation
with more emotional lyrics and more melodic instruments.
Soon after, a surge of new bands started forming and creating their own adaption of the style that Rites of Spring innovated.
The summer of 1985 became known as "revolution summer".
Good emo bands from "revolution summer" include:
Rites of Spring, Embrace, Moss Icon, Dag Nasty, Gray Matter,
Nation of Ulysses, and Fire Party.
After the disbanding of Rites of Spring,
Ian MacKaye (from Embrace) and Guy Picciotto (from Rites of Spring) formed the post-hardcore band Fugazi in the early 90s. who influenced bands such as Sunny Day Real Estate, Far, Braid, and Jimmy Eat World.
In my opinion, Sunny Day Real Estate are to mall emo, (the music that's commonly referred to as emo today)
as Rites of Spring are to emo.
They started the whole movement of mainstream "emo" bands.
Happening at the same time,
was the the unground movement of screamo.
Screamo sounded similar to emo,
but louder and with a lot more screaming and slightly different song structures.
Screamo started with bands such as Antioch Arrow, Palatka,
Portraits of the Past, and The Swing Kids.
The music comprised of brutal yet somewhat melodic guitars, loud, fast drums, song structures that switch from quiet to loud, and obviously, screaming vocals.
One thing that's not true is when people say real emo is a dead genre.
because, while mainstream "emo" has taken over MTV and the radio, an underground emo/screamo scene still exists.
Circle Takes the Square, Raein, Daitro, Haram, 1905, and ...Who Calls So Loud, City of Caterpillar are all examples of emo (and screamo) bands from the last eight years, most of them are still existing.
It's not a dead genre, you just have to look for the real deal.
Person1: Is My Chemical Romance emo?
Person1: Then what is emo?
Person2: *points to definition*