Frank Langfitt

Never have so many Chinese people spoken so freely than on Weibo, China's answer to Twitter. Just 4 years old, the series of microblog services now has more than 400 million users.

And, increasingly, Chinese are using it to expose corruption, criticize officials and try to make their country a better place — even as China's Communist Party tries to control the Weibo revolution.

Were it not for Weibo, you would never know Tang Hui's extraordinary story. She wouldn't be free to tell it; she'd be sitting in a Chinese re-education-through-labor camp eating porridge.

An elderly couple is winnowing rice in the front yard of their home in the tiny village of Dongjianggai, about 200 miles northwest of Shanghai. They've just watched China's incoming leaders — including Xi Jinping, the new general secretary of the Communist Party — appear for the first time on national TV.

"We don't know them," the husband, Wu Beiling, says. "Xi Jinping was just unveiled. I'm not very familiar with the rest of the members."

The Shanghai Propaganda Poster Art Center lies buried in an unmarked apartment building off the tree-lined streets of the city's former French Concession. There are no signs. You have to wend your way through apartment blocks, down a staircase and into a basement to discover one of Shanghai's most obscure and remarkable museums.

People often say China is a nation of contrasts: of wealth and poverty, of personal freedom and political limits. But that observation doesn't begin to capture the tensions and incongruities of modern life here.

For instance, in today's Shanghai, you can sip a $31 champagne cocktail in a sleek rooftop bar overlooking the city's spectacular skyline, while, just a few miles away, ordinary citizens languish in a secret detention center run by government-paid thugs.

If you followed American media in recent years, you might have thought China was taking over the planet. Recent titles at the book store have included Becoming China's Bitch and When China Rules the World.

"They are the world's superpower or soon will be," Glenn Beck used to intone on Fox News. "They always thought America was just a blip."

And when the city of Philadelphia postponed an Eagles football game a couple of years ago because of a blizzard forecast, then-Gov. Ed Rendell said America — unlike China — was becoming a nation of "wussies."

Not so long ago, many Chinese commentators wrote in a cautious, oblique style designed not to offend the nation's famously humorless leaders — then came the Internet, blogs and a cheeky young man named Han Han.

The voice of China's post-'80s generation, Han is ironic, skeptical and blunt — writing what many young Chinese think but dare not say publicly.

Now 30 years old, Han has boy-band good looks, drives race cars and has 8 million followers on the Chinese equivalent of Twitter.