A post by Sarah Palin denouncing the plans to build a Muslim cultural center in downtown New York mysteriously disappeared from Facebook on Thursday morning. Did Facebook take it down after users flagged it as hate speech? A blogger on Tumblr is claiming credit for its disappearance after he started a campaign to label it hate speech. Facebook is now investigating whether it was taken down by their automated system: "We're investigating this incident to determine whether the content in question was removed by an automated system as a result of user reports that it violated our terms,” the company said in a statement. The post has since been put back online.