SAN FRANCISCO -- The Facebook page for Gaston Memorial Hospital, in Gastonia, N.C., offers a chicken salad recipe to encourage healthy eating, tips on avoiding injuries at Zumba class, and pictures of staff members dressed up at Halloween. Typical stuff for a hospital in a small town.
But in October, another Facebook page for the hospital popped up. This one posted denunciations of President Obama and what it derided as "Obamacare." It swiftly gathered hundreds of followers, and the anti-Obama screeds picked up "likes." Officials at the hospital, scrambling to get it taken down, turned to their real Facebook page for damage control. "We apologize for any confusion," they posted on Oct. 8, "and appreciate the support of our followers."
The fake page came down 11 days later, as mysteriously as it had come up. The hospital says it has no clue who was behind it.
Fakery is all over the Internet. Twitter, which allows pseudonyms, is rife with fake followers, and has been used to spread false rumors, as it was during Hurricane Sandy. False reviews are a constant problem on consumer Web sites.
Gaston Memorial's experience is an object lesson in the problem of fakery on Facebook. For the world's largest social network, it is an especially acute problem, because it calls into question its basic premise. Facebook has sought to distinguish itself as a place for real identity on the Web. As the company tells its users: "Facebook is a community where people use their real identities." It goes on to advise: "The name you use should be your real name as it would be listed on your credit card, student ID, etc."
Fraudulent "likes" damage the trust of advertisers, who want clicks from real people they can sell to and whom Facebook now relies on to make money. Fakery also can ruin the credibility of search results for the social search engine that Facebook says it is building.
Facebook says it has always taken the problem seriously, and recently stepped up efforts to cull fakes from the site. "It's pretty much one of the top priorities for the company all the time," said Joe Sullivan, who is in charge of security at Facebook.
The fakery problem on Facebook comes in many shapes. False profiles are fairly easy to create; hundreds can pop up simultaneously, sometimes with the help of robots, and often they persuade real users into friending them in a bid to spread malware. Fake Facebook friends and likes are sold on the Web like trinkets at a bazaar, directed at those who want to enhance their image. Fake coupons for meals and gadgets can appear on Facebook newsfeeds, aimed at tricking the unwitting into revealing their personal information.
Somewhat more benignly, some college students use fake names in an effort to protect their Facebook content from the eyes of future employers.
Mr. Sullivan declined to say what portion of the company's now one billion plus users were fake. The company quantified the problem last June, in responding to an inquiry by the Securities and Exchange Commission. At that time, the company said that of its 855 million active users, 8.7 percent, or 83 million, were duplicates, false or "undesirable," for instance, because they spread spam.
Mr. Sullivan said that since August, the company had put in place a new automated system to purge fake "likes." The company said it has 150 to 300 staff members to weed out fraud.
Flags are raised if a user sends out hundreds of friend requests at a time, Mr. Sullivan explained, or likes hundreds of pages simultaneously, or most obvious of all, posts a link to a site that is known to contain a virus. Those suspected of being fakes are warned. Depending on what they do on the site, accounts can be suspended.
In October, Facebook announced new partnerships with antivirus companies. Facebook users can now download free or paid antivirus coverage to guard against malware.
"It's something we have been pretty effective at all along," Mr. Sullivan said.
Facebook's new aggressiveness toward fake "likes" became noticeable in September, when brand pages started seeing their fan numbers dip noticeably. An average brand page, Facebook said at the time, would lose less than 1 percent of its fans.
But the thriving market for fakery makes it hard to keep up with the problem. Gaston Memorial, for instance, first detected a fake page in its name in August; three days later, it vanished. The fake page popped up again on Oct. 4, and this time filled up quickly with the loud denunciations of the Obama administration. Dallas P. Wilborn, the hospital's public relations manager, said her office tried to leave a voice-mail message for Facebook but was disconnected; an e-mail response from the social network ruled that the fake page did not violate its terms of service. The hospital submitted more evidence, saying that the impostor was using its company logo.
Eleven days later, the hospital said, Facebook found in its favor. But by then, the local newspaper, The Gaston Gazette, had written about the matter, and the fake page had disappeared.
Facebook declined to comment on the incident, and pointed only to its general Statement of Rights and Responsibilities.
The election season seems to have increased the fakery.
In Washington State, two groups fighting over a gay marriage referendum locked horns over "likes" on Facebook. A group supportive of gay marriage pointed to the Facebook page of its rival, Preserve Marriage Washington, which collected thousands of "likes" in a few short spurts. During those peaks, the pro-gay marriage group said, the preponderance of the "likes" came from far-flung cities like Bangkok and Vilnius, Lithuania, whose residents would seem to have little reason to care about a state referendum in Washington. The "likes" then fell as suddenly as they had risen.
The accusations were leveled on the Web site of the gay marriage support group, Washington United for Marriage. Preserve Marriage Washington in turn denied them on its Facebook page. Facebook declined to comment on the contretemps.
The research firm Gartner estimates that while less than 4 percent of all social media interactions are false today, that figure could rise to over 10 percent by 2014.
Fake users and their fake posts will have to be culled aggressively if Facebook wants to expand its search function, said Shuman Ghosemajumder, a former Google engineer whose start-up, Shape Security, focuses on automated fakery on the Internet. If you are searching for a laptop computer, for instance, Facebook has to ensure that you can trust the search results that come up.
"If the whole idea behind social search is to look behind what different Facebook users are doing, then you have to make sure you don't have fake accounts to influence that," he said.
The ubiquity of Facebook, some users say, compels them to be a little bit fake. Colleen Callahan, who is 25, is among them. She was a senior in college when she started getting slightly nervous about the pictures that a prospective employer might find on Facebook. Like the pages of most of her college friends, she said, hers had a preponderance of party pictures.
"It would be O.K. if people saw it, but I didn't want people to interpret it differently," she said. So Ms. Callahan tweaked her profile. She became Colleen Skisalot. ("I am a big skier," she explained.)
The name stuck. She still hasn't changed it, though she is no longer afraid of what prospective employers might think. She has a job -- with an advertising agency in Boston, some of whose clients, it turns out, advertise on Facebook.
This article originally appeared in The New York Times.