Caity Weaver writes: “Once a month, most months, there happens a happening that rewards compulsive curiosity. For a few hours in the backcountry of social media, miscellaneous facts surge and swirl and billow in unison, like clouds of starlings disappearing and reforming in an empty winter sky. They flutter in from niche museums, government agencies, school libraries, and county historians—released on a summons from the National Archives and Records Administration of the United States. This confluence is known as an ‘Archives Hashtag Party.’”