The repression of Muslim Uighurs, the Tiananmen Square crackdown, and S&M hook-ups -- nothing was off-limits in the rambunctious, unfiltered chatrooms of Clubhouse, before China's censors silenced the conversation.
For around a week, robust, open discussion on China pinballed across the American audio app, recently lent an air of exclusivity after an endorsement from Elon Musk.
It offered mainland and Chinese-speaking users a rare space to dissect taboos across politics and society, a plurality of voices normally muted inside China by the Communist Party.
Then late on Monday, an error message appeared to Chinese users logging on without a VPN to establish a secure connection, a telltale sign that state censors had got hold of the debate.
"Under Xi, the ban was a matter of time," said Lokman Tsui, a communications professor at the Chinese University of Hong Kong, of the reflex to scrub unregulated social media sharpened under China's President Xi Jinping.
Users took to Clubhouse chatrooms and other social media platforms to lament the block, which closed a brief window for freewheeling exchanges in a country where overseas networks such as Twitter and Facebook have been banned.
Asked about the ban, a Chinese foreign ministry official said Tuesday he was unaware of specifics but added: "While China's Internet is open, the Chinese government manages it in accordance with the law and regulations."
Although Chinese versions of global platforms have emerged and become part of daily life, Chinese users are aware that content posted on them is monitored and censored.
It is common for social media companies to wipe content considered politically sensitive, including protests and criticism of the government, with users devising measures like screenshots and deliberate typos to skirt censors.
- 'Living a lie' -
On Clubhouse last Saturday, however, more than 1,000 users flocked to a chatroom on the mass incarceration of Uighurs and other Turkic-speaking Muslims in China's western Xinjiang region.
Rights groups believe at least one million people are incarcerated in camps in Xinjiang, but Beijing has said they are vocational training centres aimed at reducing the appeal of Islamic extremism.
At least three people identifying as Uighurs shared personal stories in the Clubhouse chat and several others said they were Han Chinese who had lived in Xinjiang.
A woman said her views changed after living abroad exposed her to more information on Xinjiang.
"I had only been living in a huge lie," she said.
But some struck a more defensive note, with a man countering that "re-education camps" were necessary.
Moderators allowed time for people to talk in the Chinese-language chatroom without interruption, in a conversation that ended the following afternoon.
On Monday, more than 2,000 users gathered in another chatroom discussing the bloody crackdown on Tiananmen Square protests in 1989, a taboo topic in China.
One said the environment was "dangerous for both sides", referring to civilians and authorities, while another called it outdated to claim that students -- who participated in the movement -- were easily "brainwashed".
People from Hong Kong and Taiwan also pitched in on, or moderated, China-related topics.
But the frank exchanges were not limited to big questions of politics.
The night after the Xinjiang chat, in another room, gay men swapped explicit stories of booty calls.
Some talked about engaging in unexpected S&M hook-ups, and others shared anecdotes about taking dates home only to be found out by their parents.
But the door soon slammed shut on unfettered discussion.
The space for free online discussion has "been drastically reduced" since 2013, the year Xi became president, added Emilie Frenkiel, associate professor at Université Paris Est Créteil, who researches political participation and representation in China.
But she added that the chance for open discourse on sensitive topics with other Chinese-speakers like Taiwanese counterparts "even though very risky, is so rare that... many are still willing to seize it".
A search for "Clubhouse invites", previously for sale on a Chinese online marketplace, no longer turns up results.
Since the ban, Chinese speakers returning to the app discussed ways to circumvent the "Great Firewall", and a chatroom ironically praising a pro-Communist Party editor continues defiantly.
But the wider lament was for the end of a precious space for debate which flickered but was never allowed to flare.
"I came here because it did not have speech censorship," one user said.