The innocuous group, which used to sell mostly second-hand furniture and bric-a-brac, was targeted by hundreds of anonymous cyber trolls late last week.

An administrator has since been installed and has ejected more than 600 people from the group, called For Sale - Furniture and Homeware in the Illawarra.

The offensive content included fake advertisements for sex toys and sexual services, posted among genuine ads for dining chairs and coffee tables. Numerous members reported the behaviour to Facebook. It is unclear if the company acted in installing the administrator, who declined to speak to the Mercury.

In a reply to group member Nicole, of Warilla, Facebook said the behaviour didn't violate its community standards.

Nicole was among group members who, after challenging the trolls, found themselves the targets of disturbing personal attacks.

She found a photo of herself, posted with a public survey-style caption asking who in the group would "smash or bash" her.

Nicole said the group's membership swelled by more than 400, to about 8000, in the lead-up to the attacks.

"All those scumbags have gone and invited all their friends to put up rude and crude stuff," she said.

"Obviously, it totally offended me for someone to steal my profile picture and say such demoralising comments.

"Some of the ladies are quite elderly, so you can imagine them seeing pornographic material, it's totally shocked some people."

Group member Richard Kramer also publicly challenged the trolls and was attacked over his physical disability.

"I was horrified that people were listing things like a doll floating upside down in the water, advertising abortions for $450," he said. "It upsets everyday people who are just out to sell stuff or even give stuff away."

Mr Kramer has since left the group.

Numerous alternative groups have been created as a result of the troubles.

Social commentator, playwright and well-known Twitterati Van Badham said trolling was largely a gendered problem, led by mostly white, middle-class males.

They had failed to achieve real-life power and their online trolling was a kind of compensation, she suggested.

"If you're born with that privilege of whiteness, maleness and a class position that [is associated with] power, and you're not powerful, there's a lot of self-hate in that," she said.

"When people come together and bond around ideas, that's very threatening to people who are isolated."

Badham said the group's creator erred in initially making it an open page, with no administrator to oversee who joined the group and how they behaved.

She supported recent action by fellow Twitterati Clementine Ford in publicly exposing a cyber troll.

"Trolls exist because they think they have the cover of anonymity on the internet," Badham said.

"They've got to learn that there are consequences for their behaviour."