Some Facebook users on Tuesday saw notes at the bottom of posts asking whether they contain hate speech.
It looked like Facebook was trying to bolster its forever-war against hate speech on the platform, primarily fought with algorithms and human staffers, by simply asking users to call it out.
People saw the question appear on innocuous posts, including one from The Bad Apple bar in Chicago talking about menu items.
But Facebook said it didn't mean to deploy the hate-speech question, calling its appearance the accidental release of an in-house experiment.
"This was an internal test we were working on to understand different types of speech, including speech we thought would not be hate," a Facebook spokesman said by e-mail. "A bug caused it to launch publicly. It's been disabled."
The company has halted the internal test as well, according to the spokesman.
Facebook's ability to police the content on its platform has been under scrutiny since the 2016 election season, when misinformation and divisive messages marred its News Feed and advertising.
Surveys are part of its toolkit to catch a number of problems, including a recent attempt to get people to rate the credibility of news sources. With that survey, Facebook was trying to lower the visibility of false news and fraudulent publishers while promoting more trusted media.
As for hate speech, it is a problem across social media—on Twitter and YouTube, too—where the platforms walk a fine line between preventing abuse and restricting speech. YouTube, Twitter and Facebook have been accused by conservative and right-leaning groups of censoring their speech.
Facebook says it is trying to lift the quality and integrity of the content in News Feed while giving users more control over the posts and ads they see.
Tuesday was also the first day of F8, the social network's annual developer conference, where it was expected to address many of the privacy changes and quality-control measures put in effect since it was reported that data firm Cambridge Analytica allegedly abused the private information of up to 87 million Facebook users for political operations.
Just before opening F8 with Mark Zuckerberg's keynote address, Facebook announced a new privacy feature that would let people clear their history on the social network. The "clear history" feature is still in development, but set to arrive in the coming months, Facebook says.
"This feature will enable you to see the websites and apps that send us information when you use them, delete this information from your account, and turn off our ability to store it associated with your account going forward," Facebook said in a blog post attributed to Erin Egan, chief privacy officer.