Micro-blogging site has 500 million users - not all of them from China.

Many Chinese people turn to sina weibo for heated debates or simply to air their views and grievances - and some expats are turning to China's most popular micro blog to get involved in Chinese society.

"I didn't really follow any discussions at the beginning, it was all too confusing, but weibo has become a window to Chinese society," said Christoph Rehage, a 32-year-old graduate student from Germany who majored in Mandarin at the Beijing Film Academy.

Rehage started using weibo in the winter of 2011. He now spends a substantial amount of time surfing the site - which he describes as a "battlefield for debate and argument".

"It doesn't make sense to me why people dispute with each other over things that barely matter," he said.

"I'm called a picky laowai when I say China is not perfect, but when I say China is developing on the right path, people call me a foreigner hired by the Chinese government to write posts in favor of those in power."

Rehage finds the discussions on weibo more lively than those on Twitter, particularly when it comes to political news.

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"A comment by some random user can get picked up by a celebrity and forwarded tens of thousands of times, along with the comment by that celebrity," he said. "I think weibo is a tool for many Chinese people to get firsthand news, comment on and sharpen their political thinking, as well as vent anger."

Weibo offers a platform for people to ignite a heated debate or topple an official by posting comments and photos. Its capacity to gauge, sway and give voice to public opinion has attracted more than 500 million users.

"Weibo doesn't seem to be a place where soft-spoken, carefully weighed standpoints are widely heard - and you have to speak loudly and sometimes even sound radical in order to make a point," Rehage said.

"You don't see people abusing each other on the street, yet it's everywhere on weibo. To adopt the provocative humor of the site, I think that many people who bark loudly on weibo are actually tame in real life," he said.

His views were echoed by Steven Weathers, a TV host for Shanghai Media Groups International Channel Shanghai.

"While Twitter is a platform to express and encourage individual views, weibo seems to be more of a collective space for large-scale interactions and exchanges of ideas," he said.

In response to the mob on weibo, Weathers said he would stop following those people and instead follow those who brought insight to his life.

Besides gaining insight into Chinese culture, connecting with fans and boosting their popularity, some expats on weibo are trying to clear the air between two different cultures.

Hiro Yamashita, a 43-year-old Japanese scholar in Beijing, said he first joined weibo mainly to catch up with popular trends in China that he could not learn from his everyday conversations.

However, as he noticed many misunderstandings about Japan spreading on micro blogs, he started correcting them whenever he saw one.

"Once I saw a post saying how popular nyotaimori (the practice of eating sushi off a human body) is in Japan, but it's too exaggerated," he said. "I have seen Japan being praised and scolded, sometimes to extremes."

Jeremy Goldkorn from South Africa kicked off his weibo journey in August 2009. He said China's micro blog has introduced friends to him, including Shen Yuting, a Chinese man who lives in East Africa and is producing his own Chinese-Swahili dictionary.

Goldkorn said his favorite activity on weibo is watching debates between different ideological camps.

"I'm interested in China, Chinese people and the Chinese language, and weibo is a good place to discover societal trends," he said.