Yul Kwon:
The war of words between people from Hong Kong and mainland China is escalating on social media sites. A few weeks ago, we told you about how an argument on Hong Kong's subway led to a Peking University professor calling Hong Kong people "SOB's" and "dogs." Well, in response, a group of Hong Kong people bought a full-page ad in a major newspaper, the Apple Daily, calling mainlanders "locusts." With Hong Kong's skyline in the background, the ad demanded that authorities "stop the invasion." Then, a group of young Hong Kong people took to the streets to serenade mainland tourists with the song "Locust World."

On a popular mainland site, NetEase, users fired back:

"Because we understand you got rich first, we've tolerated you coming to the mainland to invest, having us work like animals for you, and letting you curse us as 'northerners.' Hong Kongers, if you didn't have us, you guys would be nothing!"

But other posts pleaded for tolerance:

"The problem can only be solved if both sides work together. Yelling at each other only shows that people have different positions. Why waste time like this?!"

Then things took a funny twist. Some mainlanders spoofed the original Hong Kong ad. This one attacks migrant workers:

"Beijingers have had enough! Beijing has already accommodated 20 million migrants. Beijing has already accepted 478,000 children that came along. Stop the endless influx of migrants into Beijing!"

And this one came from China's biggest city, Shanghai:

"Do you want to spend four billion yuan every year subsidizing the migrant population?"

The not-surprising answer: "Shanghainese have had enough!"

The parody went on to list complaints:

"We have to put up with you ruining our culture; we have to put up with the accusations by your fellow villagers; we have to put up with the uncivilized behavior of your fellow villagers."

And then it all starts to sound like the original ad written in Hong Kong about mainlanders.