It's very weird.
As far as what it's about, here ya go: ""Gangnam Style" is a Korean neologism mainly associated with upscale fashion and lavish lifestyle associated with trendsetters in Seoul’s Gangnam district (강남), which is considered the most affluent part of the metropolitan area. In colloquial usage, it is comparable to the English slang terms “swag” or “yolo”." (Urbandictionary.com)
They compare it to Hollywood. The fancy cars, pools, women, and horses are all suppost to all be a part of a "fancy life style." It's very weird.
The worst part is that this is not even the worst out there as far as K-pop (Korean Pop) goes!!
It's very popular here, it's on the radio constantly, everyone at my high school knows about it, and the cheerleaders even did a dance to it!!
I don't exactly understand what's so great about it, other that it is slightly entertaining...
The first time I saw it, my reaction was basically: this is the DUMBEST thing I've ever seen. Ever.
Edit: oops, I just realized I misspelled it in the title! *blush*