Facebook is weeding out fake "Likes" caused by spammers, malware and black marketeers as it strives to maintain credibility as an advertising platform.
Facebook announced on its blog the number of Likes, or endorsements by users, on corporate pages is likely to drop by less than 1 per cent after the upgrades are implemented.
"Newly improved automated efforts will remove those Likes gained by malware, compromised accounts, deceived users, or purchased bulk Likes."
Thanks to a growing black market, businesses can raise their profile on Facebook by purchasing thousands of Likes at a time - a practice that is forbidden by Facebook, which has over 955million users worldwide.
Many of these Likes come from fake Facebook user accounts created specifically for the purpose, while other are gained through spam-like programs that deceive users into unwittingly liking something when they perform another action, such as clicking to watch a video.
Facebook said the cleanup will benefit both users and companies that maintain pages on the network, by giving a more accurate measurement of fan count and demographics.
Ensuring the integrity of Likes is serious business for Facebook, which depends on advertising revenue from large brands and other businesses, while many ad campaigns are designed to garner Likes as a sign of consumer engagement.
"It's their currency. Facebook is playing the Federal Reserve, to take the counterfeit currency off the market to ensure that there's quality in the marketplace," said Jeremiah Owyang, a partner at research firm Altimeter Group.
The problem is not unique to Facebook, say analysts, who note that Twitter and Google also grapple with fake accounts.
Facebook estimated in its most recent 10-Q regulatory filing that 1.5 per cent of its users are undesirable accounts which violate its terms of service.
"I think what they're intending to do is get a handle on it before it gets really out of control. You can imagine no business wants to pay for advertising to fake accounts," according to Brian Blau, an analyst with research firm Gartner.