"Why were most of those killed in the earthquake children?" one post asked Thursday on FanFou, a microblogging site.
"How many donations will really reach the disaster area? This is doubtful," read another.
China is now home to the world's largest number of Internet and mobile phone users, and their hunger for quake news is forcing the government to let information flow in ways it hasn't before.
A fast-moving network of text messages, instant messages and blogs has been a powerful source of firsthand accounts of the disaster, as well as pleas for help and even passionate criticism of rescue efforts.
"I don't want to use the word transparent, but it's less censored, an almost free flow of discussion," said Xiao Qiang, a journalism professor at the University of California, Berkeley, and director of the China Internet Project, which monitors and translates Chinese Web sites.
China is well known for controlling the flow of information.
"We didn't know that hundreds of thousands of lives passed away during the Tangshan earthquake in 1976 until many years after the disaster took place," sociologist Zheng Yefu said in a commentary last week in the Southern Metropolis News.
But word about Monday's magnitude 7.9 quake spread quickly on Web sites and microblogging services, in which users share short bursts of information through text and instant messages. The services also publish the messages online.
"It all depends on the users; we don't edit it," FanFou founder Wang Xin said. "We just gather their words together."
A string of crises over the last few months - including crippling snowstorms and Tibetan protests - has taught the government a few lessons, Berkeley's Xiao said.
Government officials held a rare, real-time online exchange with ordinary Chinese on Friday to answer angry questions about why so many schools collapsed in the quake.
"They understand better now that to react slowly or to cover up in the Internet age is a bad idea," Xiao said in a telephone interview.
But the government is still monitoring the online conversation. Seventeen people have been detained since the earthquake, warned or forced to write apologies for online messages that "spread false information, made sensational statements and sapped public confidence," the state-run news agency, Xinhua, reported Thursday.
Police also warned of the spread of scam text messages asking for quake donations.
One post deleted from the popular Tianya online forum had complained about the government response to the earthquake.
"A politician visited Dujiangyan for less than two minutes, and police kept the people away. Most residents don't even know he ever came!" the post said. "Who can tell me, where is the food and water that is being promised by the city government. ... I paid 50 kuai (about $7) to get on a vehicle to drive me away from this hell."
Tianya declined comment on why the post was removed, but a customer service representative said that in general, posts may be deleted for having "sensitive words" or for not being "relevant to the theme of discussions." Company policy does not allow her to be quoted by name.
Still, fierce discussion was allowed on popular online forums about whether the Chinese government should let foreign rescue teams into the earthquake zone and why so many schools collapsed.
Many people just wanted to help, creating online projects to connect quake survivors with friends and family and to spread information about how to donate blood and money and how to adopt children orphaned by the earthquake.
Even a local government joined in. With nothing but a satellite phone, a once-quiet government Web site quickly turned itself into the only source of information from the epicenter.
"Whenever we heard any news, we immediately put it on the Web site," He Biao, director of the Aba prefecture's emergency response department, told the Chinese portal Sina.com.
The Aba site shared the first details of the missing and the dead after getting the information by satellite phone from forestry departments throughout the worst-hit area.
Phone and Internet connections were cut to the epicenter for days, but a Xinhua report Friday gave a glimpse of the network that had been in place even in one of China's more remote corners. The eight worst-hit counties had more than 16,500 wireless phone stations, Xinhua said, though about 10,000 remained damaged Friday.
A team of 12,000 technicians was working to restore the telecommunications network, Xinhua said, despite a series of strong aftershocks throughout the region.
People gathered at emergency phone stations, and at power sources to recharge their mobile phones. "A direct connection to the disaster zone!" Sina.com headlined Friday night.
"All the major online communities, bloggers, all are very eager to help. It's quite amazing," Xiao said. "I haven't seen anything like that, the freedom and the participation, how much the average Internet netizen wants to help."
The information ranged from the useful to the mundane.
"The milkman has arrived," 22-year-old British student Daniel Ebbutt noted through Twitter, a microblogging service, just hours after the quake. He lives in Chengdu, the capital of hard-hit Sichuan province. "It seems people are just getting on with things now."
But he also noted that rumors are sweeping the region via the text and online services.
One rumor, that the water might be polluted with ammonia, led to a series of posts by Ebbutt about a frantic shopping spree for bottled water.
Rumors are the downside of the free information flow, said Kevin Morris, a 26-year-old American teacher and blogger living just outside the hard-hit area of Dujiangyan, an hour's drive northwest of Chengdu.
"The official media has actually been much better at keeping people calm and is surprisingly frank with its reporting," Morris said by e-mail Wednesday. "The rumors are mostly damaging - causing people to rush out of their homes at the slightest hint of an aftershock or, now, causing people to buy as much water as possible because the government is supposedly turning off the water."