Hong Kong (CNN) -- Users of Sina Weibo, China's popular Twitter-like micro-blogging service, now have to abide by new rules aimed at preventing online rumors and other controversial posts.
The "user contracts" that took effect on Monday come as authorities put increased pressure on China's social networks to police what their users are saying.
Sina has also rolled out a points system as a way to manage users who post content that contravenes the new rules, according to documents posted on Sina Weibo's website.
Under the system, each Weibo account will begin with a score of 80 and points will be deducted for any perceived misconduct. Accounts that drop to zero will be canceled.
Weibo and rival platforms like Tencent's QQ have become hugely popular in China, with many Chinese regarding them as an important source of news and other information. Weibo is estimated to have 300 million users.
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Other banned content includes revealing national secrets, threatening the honor of the nation, or promoting illicit behavior such as gambling.
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The new rules also seek to stop the use of code words or other expressions often employed by Chinese web users to refer to controversial people or events. For example, the disgraced Chinese politician Bo Xilai was often referred to as BXL.
Doug Young, a Chinese media expert from Fudan University in Shanghai, said the steps are intended to ease Beijing's concerns about the spreading of false rumors.
"I think Sina are trying to be proactive and clean up the site and show the government they are taking steps to stop people from spreading false information or other posts that create trouble," he said.
In April, China's Internet regulator temporarily suspended the comments sections of Weibo and Tencent's QQ as a punishment for allowing rumors to spread.
Authorities also closed 16 websites and detained six people for allegedly spreading rumors of "military vehicles entering Beijing" shortly after the arrest of Bo when China's Internet was rife with talk of an alleged coup.