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Environment and politics - not celebrity gossip - dominated social media debate in 2013, aggregated data shows.
The 7.0-magnitude earthquake in Sichuan province, which left at least 193 people dead , on April 20, tops a ranking of hottest topics of the year on Sina Weibo, China’s most popular micro-blogging platform, according to data compiled by Weiboreach, a firm based in Beijing providing social-media-data analysis.
The firm applies the H-Index, usually used to measure the productivity and impact of scholarly publications, to weibo posts to measure their impact.The accumulated impact of posts related to the earthquake is almost three times higher than posts on any other topic, its data shows.
An outpouring of sympathy for the earthquake’s victims, the 100,000 people left homeless, made good wishes for those affected the single-most frequently posted message last year. The political fallout from the reconstruction effort guaranteed that the disaster continued to be a topic of debate among Internet users.
The second-most debated topic was the succession of Xi Jinping to Hu Jintao at the 12th National People’s Congress in March, followed by Typhoon Fitow in October. The rare late-season storm barrelled into China’s eastern coast in Fujian and Zhejiang province, leading to the evacuation of more than half a million people .
The poor emergency-response actions led to social unrest in Yuyao  in Zhejiang in the aftermath of the storm and the dispatch of 4,800 troops to aide rescue efforts.
Only at fourth place comes the trial of Bo Xilai , a former rising star in the Communist Party. In a first for China's courts, the Jinan Intermediate People’s Court in Shandong province, which convicted him to life imprisonment on charges of bribery, embezzlement and abuse of power, shared photos and redacted transcripts of the court proceedings on its weibo account. Within minutes they were shared thousands of times.
The secret execution of Zeng Chengjie , the man dubbed "China’s Bernie Madoff", by a firing squad in July became another hot topic, sparking debates about shadow-banking and whether Zeng was granted a fair trial and sentence.
The Communist Party’s Third Plenum in November, at which the Chinese leadership decided on the framework economic policies  for world’s second-largest economy in the coming five years, ranked sixth among the most discussed topics on Sina Weibo.
The party’s Central Committee decreed the abolition of some labour camps and the relaxation of the one-child policy at the meeting. It also declared that the market should “play a decisive role in the allocation of resources”, pointing to further economic liberalisation.
The detention of venture capitalist Charles Xue Biqun, a US citizen and once one of the most prominent commentators on Sina Weibo, in August ranks seventh among the most widely discussed topics.
Xue, whose micro-blog is followed by more than 12 million people, was detained on charges of soliciting prostitution and paraded on national television , sparking an outcry over the unusual treatment of the celebrity blogger. His detention was widely seen as a part of a crackdown to rein in online debate.
Data provided by Weiboreach to the South China Morning Post showed  a significant reduction in posts by influential users as the crackdown ensued.
1. Ya’an earthquake
2. Leadership transition
3. Typhoon Fitow
4. Bo Xilai’s trial
5. Zeng Chengjie’s execution
6. Third Plenum
7. Charles Xue’s detention
8. Moon landing
9. Beijing airport bombing
10. Qingdao’s pipeline explosion