Four people have been arrested in China over posts made on Twitter-like website Sina Weibo, state media has reported.
The users are said to have "incited dissatisfaction with the government" by spreading rumours about a "hero" used in various propaganda posters.
Prosecutors said the group had been profiting from the activity.
The arrests come at a time when the Chinese authorities are seeking to reassert strict rules around public discourse.
"On one hand they know how popular this platform is, but they are also aware it can be a disruptive force," said BBCChinese.com editor Zhuang Chen.
"This is one of the main campaigns that the Chinese public security ministry is carrying out - to send out a clear message."
The arrested users were said to have spread rumours about Lei Feng, a deceased soldier who is often used as an example of the model Chinese citizen, a Communist Party devotee.
"Information that seriously harmed the image of Lei Feng was rapidly transmitted across the internet," the People's Daily reported, "and Lei Feng's glorious image was quickly brought into question."
With almost 300 million users in the country, the social network is booming - even attracting famous names from outside of the country.
The likes of Robert Downey Jr, Paris Hilton and basketball star Kobe Bryant all have a presence on the site - although they are mostly there for marketing purposes rather than the more general discussion often found on Twitter.
Earlier this month, the government brought together some of Sina Weibo's most popular users to discuss their use of the platform.
The meeting, held at the headquarters of China's state TV network, set out seven key "minimums" for behaviour.
They included vaguely set standards for upholding the national interest, keeping with socialist values and maintaining public order.
Technology blog TechInAsia.com noted that the seven minimums appeared to be widely supported by the Sina Weibo community, but that some of the comments supporting them may have been posted by paid "opinion managers".