Here's the world's most popular music video, with 233,000,000 views on Youtube:
Being an old coot, I'm out of touch with kids these days and what they think is cool. But, still ...
A tubby, not too young South Korean singer (?) named Psy parodies (?) the lifestyle of the expensive Beverly Hills-like Gangnam district of Seoul, set to a generic beat while dancing not terribly well in a silly fashion, with guest appearances by Korean celebrities I've never heard of.
There are always a lot of jokes out there, so why do people around the world enjoy getting this joke so much at this point in time?
I'm guessing that people are, in some sense, paying tribute to South Korea's long emerging national self-confidence. The South Koreans make good cars, they make good phones, their popular culture is livelier and more masculine than Japan's at present, and so forth. So, this one piece of flotsam gets picked up by a big national wave and is hurled forward. In contrast, you are less likely to see an international pop phenomenon emerge from countries that are mostly treading water, like, say, the Philippines.