Things have been getting nasty in parts of the PRC lately,

and here's two things. Insty points to this roundup, and Stingray had a link to this on China's economic problems. Including
Recent figures do not bode well for China’s current economic forecast. Unemployment has risen dramatically over the last few months, with an estimated 20 million of China’s 130 million migrant workers unable to find work. Textile factories are closing by the thousands leaving large swaths of China’s textile workers unemployed. The World Bank on Wednesday lowered its economic growth forecast for China this year to 6.5 percent, down from 7.5 percent at the end of last November, after huge falls in exports and shrinking private sector investment.

As a large country with an unusually high degree of openness to the world economy, China depends on other countries, notably the United States, for its domestic prosperity and stability. Thus China is highly vulnerable to shocks from the international economy. The latest figures show foreign trade accounts for 75% of China’s GDP - an astounding figure when put in perspective.
I'm not an economist, but for a nation that size to depend on foreign trade for that much of GDP... that's not good.

Also,
Consequently, since 1989, the term “social stability” became a fixture of CCP rhetoric. Stripped down to essence however, this is merely a euphemism to convince the Chinese public that Communist Party rule is essential for maintaining order and prosperity, and without it, a country as large as China could descend into civil war and chaos. In their speeches, the leaders make no secret of their anxieties and social unrest, frequently using the catchphrase ”维护社会安全“ or “maintaining social order” as the overarching principle of Chinese development.
"Maintaining social order"; translation, "The Party is your best friend and leader, remember it or else."
To be sure, it is easy to see why CCP leaders are obsessed with preserving social order. There are signs all around them of burgeoning social unrest that Beijing is acutely aware of. Official statistics indicate that there were 58,000 “incidences of social unrest” in 2003, 74,000 in 2004, and 87,000 in 2005. Scanning the horizon from Zhongnanhai, the government epicenter in Beijing, CCP leaders see nothing but the spector of inchoate social unrest threatening the legitimacy Communist Party rule.
Remember that ancient Chinese curse "May you live in interesting times"?