As more than 9 million Australians flock to Facebook every day, the social media giant has, quite inadvertently, become a major player in the e-commerce market.
In addition to endless selfies, the site is now awash with online bazaars, as users hock everything from household items, to property, to personal services such as yoga classes, and to customised venetian blinds.
Many of the small community groups now boast thousands of members and the rapidly proliferating new model of e-commerce is challenging established digital behemoths such as eBay and Amazon.
Karan James, 41, is an old hand at selling wares online. But, after more than a decade as an eBay seller, Ms James made the switch from the multinational e-commerce company to Facebook's online community groups.
Ms James, like many sellers, was enticed by Facebook's fee-free platform where the marketplace is governed by a "local pick-up" ethos rather than the postage of goods.
"My main reason for walking away from eBay was because I got sick of the fees," she said, referring to the charges the site imposes for each sale advertisement.
Ms James is now an administrator of the Sydney-orientated Eastern Suburbs Buy Swap and Sell page, which is rapidly approaching 10,000 members with 50 requests a day to join.
"People love a bargain. You see things flying out the door when they are really, really cheap."
Leslie Kelcey, who administers three separate groups marketed towards residents in Sydney's western suburbs, spends an hour a night vetting potential members to ensure they are not overseas buyers or sellers.
"The whole reason of not being on eBay is to avoid the postage fees. If you don't mind driving to pick it up, we'll usually let you in," she said.
In an average day's trade, sellers will post up to 120 items on the groups' pages to a rapacious audience who are also looking to "cut out the middle man", she said.
The popularity of these community-run groups stands in contrast to Facebook's Marketplace portal, a failed attempt to compete with eBay and Craigslist that it offloaded in 2009.
The social media giant has taken notice of the new trend and in February rolled out features to improve the groups, including templates for posting items and categories to make browsing easier.
Sellers can now also request a "recommendation" from buyers, similar to eBay's rating system.
Online consumer behaviour expert Brent Coker, from the University of Melbourne's business school, said Facebook's moves to improve trading groups were a precursor to its inevitable monetisation of them.
"What they will likely do is offer the classic 'freemium' model for which they are well known: 'You can have this for free, but we've got some extra tools here to make it easier for you,' " Dr Coker said.
He said the strategy would most likely include a peer-to-peer payment system such as eBay's PayPal, which escrows money to minimise the risk for buyers and sellers.
"Facebook have been full-on with their monetisation strategy since [their sharemarket launch], so the days of building your communities for free and getting your follower to see your stuff for free are slowly disappearing."
