James Martin/CNET

Twitter is stepping up its battle against user abuse and harassment with new rules that prohibit the posting of revenge porn -- images of nudity or sexual acts posted without the subject's permission.

Twitter said Wednesday it would lock user accounts and hide content reported as being in violation of the new policies. User found to be posting such content for the purpose of harassment will have their accounts suspended, the social network said in an FAQ.

The changes, which Twitter said went into effect Wednesday, come as the social network grapples with bullying behavior it says is driving away users.

One of the changes appears in the private information section of Twitter's rules for content boundaries (new text is highlighted by CNET):

You may not publish or post other people's private and confidential information, such as credit card numbers, street address or Social Security/National Identity numbers, without their express authorization and permission. You may not post intimate photos or videos that were taken or distributed without the subject's consent.

Twitter made a similar revision to its Abusive Behavior Policy:

Users may not make direct, specific threats of violence against others, including threats against a person or group on the basis of race, ethnicity, national origin, religion, sexual orientation, gender, gender identity, age, or disability. In addition, users may not post intimate photos or videos that were taken or distributed without the subject's consent.

Combating harassment and bullying behavior has become a very public fight for Twitter. In a series of memos to employees in February, Twitter CEO Dick Costolo took personal responsibility for what he called an inadequate response to the chronic abuse and harassment that occurs daily on the social network and vowed to take stronger action to eliminate the activity from the microblogging platform.

"We suck at dealing with abuse and trolls on the platform and we've sucked at it for years," Costolo wrote in one of the internal memos. "It's no secret and the rest of the world talks about it every day. We lose core user after core user by not addressing simple trolling issues that they face every day."

Harassment, while not a new occurrence on the social network, has taken a more public spotlight in recent months. Robin Williams' death in August led some Twitter users to sending vicious messages to his daughter, prompting her to delete the app from her phone. That same month, Anita Sarkeesian, an academic highlighting how women are portrayed in video games, was so disturbed by the tweets she received that she fled her home for fear of safety.

Until recently, Twitter had few ways to control vitriolic or abusive messages its members send to each other. In an attempt to reduce that behavior, the social network unveiled a new set of tools in December to help its members combat harassment and report abusive behavior.

[Via Buzzfeed]