In the first few months of 2020, wild conspiracy theories about Bill Gates and the new coronavirus began sprouting online. Gates, the Microsoft co-founder and billionaire philanthropist who has funded efforts to control the virus with treatments, vaccines and technology, had himself created the virus, argued one theory. He had patented it, said another. He’d use vaccines to control people, declared a third. The false claims quietly proliferated among groups predisposed to spread the message — people opposed to vaccines, globalization or the privacy infringements enabled by technology. Then one went mainstream.