Cough.
Most dubstep coming out of america is actually a subgenre called "brostep".
Skrillex is kind of the mascot of the brostep genre. Most of it generally involves a verse/chorus format.
The verses are reminiscent of house/trance and the choruses are "Drops" which for the most part are just hideous treble noises that are reminiscent of a broken dial up modem.
With all that being said, I don't like "brostep" at all.
Dubstep then. What is it?
Dub: "is a genre of music which grew out of reggae music in the 1960s" 2- step garage: "is a typically English style of modern electronic dance music, and a relatively popular subgenre of UK garage"
Here's a more proper example of what dubstep really is.
http://www.youtube.com/watch?v=GHcZLvWBM9A
Another guy I happen to enjoy a lot is Skream, especially his earlier stuff.
Take for example this song.
http://www.youtube.com/watch?v=UygFvOhkCnQ
The song is all about the complexities in the beat, and the complimentary bassline. True dubstep is all about the groove. You'll know it when you hear it. Brostep? Well, it's all about who can make the nastiest sounding drop. Literally. And to me, that's not appealing.