Facebook and the state of Washington sued a company on Thursday, Jan 26, they accused of a practice called "clickjacking" that fools users of the world's top social network into visiting advertising sites, divulging personal information and spreading the scam to friends, Reuters reports.

The scheme, also known as "likejacking" because victims are tricked into using Facebook's "Like" button to perpetuate it, has grossed $1.2 million a month for the Delaware-based firm, Adscend Media, according to the state attorney general's office.

Adscend profits from the scam by collecting money from its advertising clients for every Facebook user unwittingly misdirected to a target ad or subscription service, the plaintiffs said.

Two separate but similar claims filed in federal court by the state and Facebook accuse Adscend of violating federal and state statutes outlawing misleading or deceptive commercial electronic communications and unfair business practices.

The legal action is believed to mark the first time any state government has gone to court in a crackdown against spam spread by Facebook, the world's most widely used social media network, said Paula Selis, senior counsel for the attorney general.

She said schemes such as clickjacking have grown steadily more pervasive, and that millions of Facebook users have probably been exposed to Adscend's spam.