Washington State Attorney General Rob McKenna and Facebook today announced a lawsuit against the co-owners of Adscend Media, LLC, an ad network that is alleged to develop and encourage others to spread spam through misleading tactics, including the one known as "clickjacking."

If you use Facebook, the world's top social networking site, you may have "liked" an Internet scheme without even knowing it - and unwittingly helped spread the scam to your Facebook friends.

"We don't 'like' schemes that illegally trick Facebook users into giving up personal information or paying for unwanted subscription services through spam," McKenna said during a news conference at Facebook?s Seattle Office. "We applaud Facebook for devoting significant technical and legal resources to finding and stopping scams as soon as possible - and often before they even start. We?re proud to join forces in order to protect Washington consumers."

Facebook, which filed its own lawsuit against Adscend and its owners today, welcomed the Attorney General's action. "Security is an arms race, and that's why Facebook is committed to constantly improving our consumer safeguards while pursuing and supporting civil and criminal consequences for bad actors," Facebook General Counsel Ted Ullyot said.

Here's how scams, such as the ones described in the lawsuits, work:

Scammers design Facebook Pages to look like they will offer visitors an opportunity to view salacious or provocative content. They condition viewing this content on completing a series of steps that are designed to lure Facebook users into eventually visiting websites that often deceive them into surrendering their personal information or signing up for expensive mobile subscription services.

First, Facebook users are encouraged to click the "Like" button on the scammers' Facebook Pages, which then alerts their friends to the existence of the page. Then they are told that they cannot access the content unless they complete an online survey or advertising offer. In one example noted in the complaint, the scammers overlay the Facebook "Like" button with a link that promises to reveal the results of: "This man took a picture of his face every day for 8 years!!" Of course, the promised content often does not exist and the tricked user is then directed through a series of prompts taking them off of Facebook and through a host of unrelated advertising and subscription service offers, where the scammers receive money for each misdirected user.

In some cases, Facebook users don't even need to click the "like" button to spread the spam on their Facebook pages. In the process called "clickjacking," a hidden code in enticing-looking links activates Facebook?s "like" function and puts it on the users' friends' news feeds.

Adscend spam lined the defendants? pockets with up to $1.2 million a month, according to Assistant Attorney General Paula Selis, who heads the office's Consumer Protection High-Tech Unit.

The Attorney General's lawsuit was filed in U.S. District Court in Seattle against Delaware-based Adscend and co-owners Jeremy Bash of Huntington, West Virginia and Fehzan Ali, of Austin, Texas.

The Attorney General's Office asks the court to enjoin the defendants from future violations, award damages and impose civil penalties, costs and fees.

Facebook's similar, separate lawsuit against Adscend and its owners was filed in federal court in the Northern District of California.