Here is video to show you some dancehall moves and have a look at the DJ, he is more than into it.

http://www.youtube.com/watch?v=OZkXIMk-M7M

If you notice carefully, whatever they are saying they are using their bodies to do the action. In Jamaica, the singer or rapper is called a DJ. It's used as a noun as well.

I can't say that I am really into Dancehall reggae, but I do love traditional and dub reggae styles. The Dancehall stuff does nothing for me, although I don't hate it either.

To each their own however. Let me stick with my dub though! :)

That's what the world and music an interesting place, people have different styles of music and living. In doing that, there is also much to be learnt and enjoyed and so many choices to choose from.

Is Dancehall differentiated by this or is it just the choreographed dancers that do this? Because to me it seems fairly common for music videos to have choreography that matches what they are saying. You can't sing about being suicidal and bounce around like a monkey and be taken seriously.

Dancehall is a type of Jamaican popular music which developed around the late 70's, with exponents such as Yellowman and Shabba Ranks. It is also known as bashment.

The style is characterized by a deejay singing and rapping or toasting over raw and danceable music riddims. The rhythm in dancehall is much faster than in reggae, sometimes with drum machines replacing acoustic sets. It may be the predecessor of Hip-Hop. In the early years of dancehall, some found its lyrics crude and bawdy ("slack"), particularly because of its sexual tones, popular among youths in Jamaica. Like its reggae predecessor it eventually made inroads onto the world music scene.

This deejay-led, largely synthesized chanting with musical accompaniment departed from traditional conceptions of Jamaican popular musical entertainment. Dub poet Mutabaruka maintained, "if 1970s reggae was red, green and gold, then in the next decade it was gold chains". It was far removed from its gentle roots and culture, and there was furious debate among purists as to whether it ought to be considered some sort of extension of reggae music.[1]
from wikipedia.com

I didn't see anything in the article to suggest that the dances are done to reflect the lyrics. It could be true but I would imagine they would mention it if it were a major component. That aside I do listen to dancehall reggae. Its rather nice and the idea behind it makes it easy to use when you feel like partying but not like DJing your own party.