Reports of nudity and the use of false identities account for most of Facebook’s content takedowns, according to a study released this week by Onlinecensorship.org, a project of the Electronic Frontier Foundation and Visualizing Impact that advocates for free speech on social media platforms.

Launched last November, Onlinecensorship.org asked users to submit instances of their content or accounts being removed on Facebook, Instagram, Twitter, YouTube, Flickr, and Google +. Between November and March, the site received 161 complete submissions, most of them for content removed from Facebook.

It’s a small sample, but it does provide a picture of what it’s like for users who have their accounts or content removed.

Onlinecensorship.org received 119 reports from Facebook users. Sixteen respondents (13 percent) said Facebook asked them to show identity to prove that their accounts were under their real names. “Facebook employs a strict policy requiring individuals to use a name ‘their friends or family know them by’ on Facebook,” the report notees. “This policy has come under scrutiny by the media and rights groups, particularly for the impact that it can have on marginalized communities.

Ten of the users who had their accounts suspended based on their names said they appealed the decision. Forty percent of those who appealed said Facebook never replied to them. Half of the users who didn’t appeal said they didn’t know that they could even ask Facebook to reverse the decision.

At least four of the users said their accounts were reported for false names because of comments they made or debates they participated in. One user described how his account was taken down:

The user posted a piece of controversial content criticizing the movement for transgender rights. The same day, Facebook contacted him to request proof of identity. The user suspected that he had been reported by someone who disagreed with his politics. He did not comply with Facebook’s request for identification, and after seven days, his account was suspended. He says it has remained in a state of review for several months. It should be noted that we received similar reports across the political spectrum.

Facebook allows users whose accounts are suspended to submit identification to show that they are in fact using their real name. Some users “reported that the process for recovering their accounts or appealing Facebook’s decision was confusing, and that Facebook’s decision-making process was impenetrable and impersonal.” Here’s how one user described their experience:

The user, who is from a non-English speaking country, has a name likely to be unfamiliar to English speakers. She complied with Facebook’s initial request for ID. The ID type she submitted apparently qualified, but Facebook suspected that it was not valid and requested two further forms of identification, which she provided. Still, Facebook did not restore her account, and she says they offered no final justification for this decision beyond skepticism of the submitted IDs.

Facebook’s guidelines regarding nudity were also somewhat unclear. The social network allows breastfeeding images and photos of art containing nudity, but users reported that they’ve had both types of photos removed. Several users also reported that educational information on sexual health was censored:

[One] user, an award-winning photographer whose photographs have been exhibited in world-class museums, was banned several times, for 30 days each, for posting fine art nude photographs. Although the user appealed, the content was not restored. The user states: “I regard my fine art photographs to be every bit as much art as any representation of a drawing, painting or sculpture” and notes that in his jurisdiction, female toplessness is legal in public.

Regardless of the reason an account or content was flagged, users across various platforms said they found the companies’ appeals process frustrating and opaque. According to the report, only four users who appealed had their account or content restored. Nearly 50 users didn’t hear back from the companies:

From the report:

Ultimately, this reflects a critical need for greater clarity from the companies on what options are available to users when their content and accounts are taken down, and more accountability to help them get back online. User reports reflect a deep distrust in the companies to act in the user’s best interest, and a frustration with what they perceive to be insufficient resources and attention paid to this issue.

The full report is available here.