Social news site Reddit is in virtual lockdown in protest over the sacking of popular employee Victoria Taylor.
Ms Taylor oversaw the "Ask Me Anything" (AMA) section of the site that interviewed celebrities, politicians and other newsworthy figures.
About 100 chat sections, or sub-reddits, that together have millions of readers are believed to have been shut.
Reddit's only comment about the issue has been to say that it did not talk about "individual employee matters".
The protests were led by the volunteer moderators of the AMA section, which said in an explanatory posting that they needed Ms Taylor to keep the sub-reddit functioning. Ms Taylor helped organise guests for AMAs and worked to verify that people due to answer questions were who they said they were.
There had been no explanation of why she was suddenly sacked, said the moderators.
"We all had the rug ripped out from under us and feel betrayed," said one of the AMA moderators in a separate message.
Later on, protesters said the chat rooms were closed "due to underlying resentment against the admins for running the site poorly".
Reddit staff were "being uncommunicative, and disregarding the thousands of moderators who keep the site running", they said.
The closures have snowballed and have made large sections of the site unreachable.
There have been suggestions that Ms Taylor was sacked following an AMA with American civil rights activist Jesse Jackson.
Ms Taylor said she was "dazed" by the swiftness of her departure in a very brief response to a message asking her about the sacking.
The protest follows another "Reddit revolt" that took place in June when the site decided to ban some sub-reddits it said were involved in harassing and abusing people in real life.
Many people have pledged to abandon the site for rivals such as Voat and Frizbee.
Reddit is one of the most widely used sites on the web with more than 7.5 billion page views a month.