(YouTube screengrab, sgal901)

As pro-anorexia sites, selfharm photo groups and videos that judge one’s beauty proliferate, sites such as Tumblr and Formspring are wrestling with whether they should remove the troubling content from their sites.

Tumblr took action this week to stop a disturbing trend on its site — pro-anorexia blogs. Many of these “pro-ana blogs” encourage teens to starve themselves or give them advice about get skinny fast. “Make your calories count,” one blogger wrote.

“These girls I always see pictures of, with their tiny noses and beautiful faces, gorgeous bodies... That’s all I want,” another wrote.

In a staff post this week, Tumblr laid out a new content policy that prohibited such blogs. “Don’t post content that actively promotes or glorifies self-injury or self-harm,” Tumblr wrote.

The company sought not to isolate Tumblr users who might need help, however, saying it will accompany searches for self-harm terms in the future with a warning that directs readers to help lines run by organizations like the National Eating Disorders Association.

On YouTube, girls (and some boys) make videos asking commenters to tell them if they are pretty or ugly.

“A lot of people call me ugly, and I think I am ugly,” sgal901 says in her video as she shows a series of pictures of herselfand ends the video with: “So, yeah, tell me what you think.” The video, which has been watched by more than 3.6 million people, has received 37,000 “dislikes.”

Similar videos feature girls asking their viewers whether or not they are skinny, which some worry could trigger eating disorders.

YouTube said in an emailed statement that their Community Guidelines “prohibit videos or comments containing harassment, threats, or hate speech — we encourage users to flag material so we can quickly review it and remove anything that breaks the rules.”

But what if the speech is self-hate speech?

On Instagram, where “tags” are used to differentiate between subject matter, many of the tags used by teens are equally troubling. One such tag, “self harm,” includes dozens of graphic pictures, including several showing a girl after she cut herself. The photo site, which is fairly new, has no known policy against such tagging. Instagram did not immediately respond to request for comment.

Formspring, a Q&A app, became popular among teens over the last several years but wasn’t so popular with parents. The start-up was plagued by incidents of bullying, in large part because users can ask questions of others anonymously. The bullying ranged from a few words of intimidation to a list of laid-out threats.

Last March, Formspring announced it planned to tackle the bullying through a partnership with MIT’s Media Lab, which would develop detection tools to find “problematic content.” While the bullying has declined on the site, some users say it still exists.

Teens have shared their insecurities online for years. The “Am I pretty?” trend, for example, can trace its roots to Hot or Not.com, a site launched in 2000 that allows anonymous Internet users to rate men and women on their attractiveness.

Sites are now acknowledging the potential harm in allowing teenagers to post personal angst so publicly.

“How do we get YouTube to make this illegal?” asked Katie Baker at Jezebel. Or any social media or blogging site, for that matter?