Facebook said on Friday it will cleanse pages of fraudulent "Likes" that have been injected by scammers to impart a false sense of popularity on profiles.
Users of Facebook can "Like" pages, a vote of approval that can help expose a company's brand to a user's friends and build momentum around advertising campaigns.
Despite Facebook's closed network that requires users to register using their real identity, the social network is still gamed: users can be tricked into liking something, malicious software can be used to infiltrate accounts and other scammers have set up businesses selling "Likes" in bulk in violation of Facebook's terms of service.
The security announcement comes as Facebook is under intense pressure to prove itself as a powerful and profitable digital advertising platform. Facebook said it has always had systems to eliminate fraud, but that it has now "increased our automated efforts."
"A Like that doesn't come from someone truly interested in connecting with a page benefits no one," the company said. "Real identity, for both users and brands on Facebook, is important to not only Facebook's mission of helping the world share, but also the need for people and customers to authentically connect to the pages they care about."
Facebook sought to reassure users, saying that less than 1 percent of Likes will be removed on average from a page.
The company has already faced questions over the legitimacy of clicks on the advertisements it sells. In July, a company called Limited Run, which has a platform used for selling digital music and merchandise, said it believed only about 20 percent of the clicks it paid Facebook for resulted in users landing on its website.
Limited Run, based in Manorville, New York, declined requests for interviews after its accusation. It deleted its Facebook page but maintains a presence on Tumblr and Twitter.
Shuman Ghosemajumder, a former Google employee who headed the company's efforts to fight click fraud, said in a recent interview that Facebook would have much more insight into questionable clicks than could be seen from the outside by an advertiser such as Limited Run.
For instance, Facebook can see how long a user's account has been open and monitor activity for suspicious behavior, such as if the user is liking hundreds of pages, where the clicks originate from and if the user has an irregular profile, such as having no friends.
People may think it's to the benefit of companies such as Google and Facebook to allow a bit of click fraud, but the true economics are that "if you provide best ROI [return on investment], all advertisers have an incentive to move their ads with you," said Ghosemajumder, who is now working with Shape Security, a start-up specializing in security for social networking sites.
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