Reggae is the musical voice that the people of Jamaica have used to tell the world about their history, about their cultural uniqueness, and about their historical and social struggles against a system that, for centuries, had done nothing but enslave and marginalize the Jamaican people.
Although Reggae, as a genre, did not become official until the 1960s, its salient traits had been put to use through the folkloric tradition of passing down stories, emotions, and memories through song.
The first salient trait is that the language and verbiage used as lyrics feature the slang of the ghetto. Reggae is supposed to be the poor man's voice, and the final word of the socially vindicated. Hence, true Reggae will manifest itself in street jargon.
Since a vast majority of black Jamaicans follow the Rastafarian political and religious movement, Reggae has become almost completely associated with the Rastas particularly in that the (original) topics of most reggae songs do speak about Rasta beliefs such as African repatriation, and the liberation from the "mystical" punishment by the white race. However, it is the Rastafarian tradition (and not the Reggae musical genre) which has propelled the commonly-called "Reggae" style of wearing dreadlocks, smoking marijuana, and adopting vegetarianism (prophet Garvey, 1953). Since the connection is quite strong, the terms "Rasta" and "Reggae" have almost become used interchangeably.
The book History of Reggae (2003) explains that Reggae is a combination of folk music, emphasis on the bass as its lasting undertone, and a combination of African/European beats known as "mento". It was not until the 1960's that a more defined form of reggae became what we know as modern reggae today. The most important thing to consider, however, is that Reggae music is meant to give a message; it is "task" music, and not mere entertainment. The message is often a social statement associated with the Rastafarian philosophy.
Therefore, aside from its traits in form and content, Reggae is a symbol of cultural and social pride that gives a voice to a population that was once abused and enslaved in its own territory.