Credit Sam Hodgson for The New York Times
On Monday morning, Facebook introduced Marketplace, a new section on its mobile app that allowed its users to buy and sell things to their friends and to strangers.
By the evening, the social giant was apologizing for an issue with the section, which featured some posts that would not have been out of place on the online black market Silk Road, which was shut down by the F.B.I. in 2013.
Illegal drugs. Dogs. Guns. Sexual services. Baby hedgehogs. Selling all of these items and services on Facebook goes against the siteâs commerce policy. And all of them were available on Marketplace on Monday.
Mary Ku, Facebookâs director for product management, who had cheerfully introduced the Marketplace app in a blog post earlier in the day, issued a statement saying that a technical issue had prevented Facebookâs reviewing system from identifying posts that violated its commerce policies and community standards.
She said that the issue had caused âcertain posts with content that violated our policiesâ to be visible to users.
âWe are working to fix the problem and will be closely monitoring our systems to ensure we are properly identifying and removing violations before giving more people access to Marketplace,â she said. âWe apologize for this issue.â
In her blog post Monday morning, Ms. Ku said that Marketplace had been introduced as the company recognized that its users had been buying and selling products and services through Facebook groups. She wrote that âmore than 450 million people visit buy and sell groups each month.â
Users who bought and sold products within groups had also violated the websiteâs commerce policy. In July, Mike Monteiro, a web designer who started a campaign to help monitor the social network for sales of guns, said that he had reported about 500 posts or groups that violated Facebookâs ban on weapons sales in the past month, and that the website had taken down only about two-thirds of them.
Credit Stephen Lam/Getty Images
Facebook has natural advantages as a digital bazaar. Its core purpose as a social network would allow users to more easily avoid anonymous strangers and dubious deals that are available on sites like Craigslist, which allows for anonymous posting.
And according to the companyâs first-quarter results this year, Facebook already takes up an enormous portion of its usersâ days, making any kind of new service a potentially attractive option.
Others are critical of the marketplace effort. Dan Rosensweig, a former executive at Yahoo, expressed his skepticism in an appearance on CNBC on Tuesday.
âWhy would I leave Amazonâs marketplace or eBayâs marketplace or anybody elseâs marketplace to go to Facebook unless I thought I could sell more or make more money?â he asked.
On the same program, Mike Isaac, a technology reporter for The New York Times, noted that it had been difficult to monetize such marketplaces, but that the possibility of keeping users hooked to Facebook made some headaches worthwhile.
Marketplace is being introduced gradually and was not available to all the appâs users on Monday. Facebook plans to make the app available to users in the United States, the United Kingdom, Australia and New Zealand within the next few days. It will be available on desktop in âthe coming months,â the company said.