With the option to hide behind avatars, handles, and screen names, people can be downright mean, even libelous, while communicating online. When defamatory statements are published online and a victim chooses to take action, who is to blame?

For websites like Tumblr and Twitter, which provide outlets for anyone with a username to publish content, the answer is somewhat complicated. But one thing is certain—it’s not them.

Under Section 230 of Title 47 of the United States Code, passed as part of the Communication Decency Act of 1996, web hosts have protection against legal claims arising from hosting information written by third parties. This includes content such as hate speech and sex trafficking.

During a March 9, 2014, SXSW Interactive panel “The Fragile Law that Protects Online Speech,” Ari Shahdadi, general counsel to Tumblr, explained how the company applies Section 230 to cases where unhappy users ask for negative posts concerning them or their affiliated groups to be removed from the site, sometimes threatening legal action. Examples included rants against ex-boyfriends and bad business reviews, which Shahdadi noted are protected under the First Amendment. Taking them down, he argued, might discourage the positive grassroots conversations that also take place on the site. “You’re either committed to free speech or you’re not,” he noted.

Tumblr, however, has chosen to remove select posts, such as uploads that glorify self-harm.

According to Ellyn Angelotti of the Poynter Institute for Media Studies and Catherine Cameron with Stetson University College of Law—panelists in the March 10, 2014, conversation “Twibel: Fight Bad Speech with More Speech”—the social media site Twitter is facing similar questions when dealing with libelous posts. But despite numerous instances of online defamation, few cases have actually gone to court. Angelotti and Cameron, along with audience members, speculated that this could be a reflection of the costs associated with suing or simply an understanding that “that’s just the way things are online.”

Recognizing that traditional mediation and dispute resolution approaches are not always practical in online defamation cases—where more often than not, a victim desires for the situation to simply never have happened—Angelotti and Cameron discussed alternative approaches, such as community monitoring, as a system for combating libel.

Both Tumblr and Twitter offer community guidelines. Still, questions regarding the rights and responsibilities of both users and hosts linger and appear likely to remain present until additional legislation is passed.