Facebook may require real names to post on the social network's so-called "walls," but for the company's own real-life equivalent, that does not appear to be the case. As a result, co-founder Mark Zuckerberg reportedly posted a private company-wide memo condemning a particular wave of anonymous activity on its "signature wall."

According to a Gizmodo report, Zuckerberg took issue on Wednesday with someone crossing out part of the phrase "Black Lives Matter"—which was written on the company's giant dry-erase wall next to other staffers' and guests' signatures and drawings—and changing it to read "all lives matter." The Zuckerberg memo alleged that this had happened multiple times to the Facebook signature wall, and he called out the anonymous activity: "Despite my clear communication at Q&A last week that this was unacceptable... this has happened again."

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The story also calls to attention Facebook's publicly disclosed diversity figures, which counted a 2-percent count of African-American employees in both 2014 and 2015. Zuckerberg's memo, with mentions of "a history of oppression and racism," clarified his issues with the tags, seemingly targeted at the company's non-black staffers: "'Black lives matter' doesn't mean that other lives don't; it's simply asking that the black community also achieves the justice they deserve."

Facebook has remained consistently opposed to anonymous posts on its virtual walls, a fact that led pseudonymous users—particularly performers and users who went by names other than those on their licenses—to fight back against the company's policies in 2014. Those efforts led to a promise of "substantive changes" in favor of nicknamed users, but Facebook never followed that promise up with any major announcement.