Emo music is something that is rather ambiguously defined. It can be something that has heavy punk chords and influence such as what we've heard from the Sex Pistols, but it can also be something with soft melodic characteristics like what we've heard from the Cure. This is why emo is such a hard concept to define. It is an expression of emotion in some way.
Emotions can vary from angry to sad to happy, and emo music is an expression of those experiences as well as their range. When it comes to the emo music scene, there are many bands that may claim to be the founders of the cultural movement. However, you would have to look across the pond to gloomy England to find the real Kings of emo music. The Cure have been going strong now for over 20 years, writing songs that could make any 16 year old boy break into tears, even the football players. Their catchy guitar riffs and honest, emotional vocals have been mimicked by almost every emo artist to date. Another band from across the pond that has definitely influenced the emo music scene is Depeche Mode. They might be a primarily electronic band, but their moody lyrics and loner style has crept into every facet of the emo scene from emo-corner.ehehe