Michigan kidnapping plot, like so many other extremist crimes, foreshadowed on social media

Online declarations, brimming with hatred and potentially violent intent, have become staples of extremism-fueled crime, from police killings to synagogue massacres to bombing plots. Before they become real, these plots percolate online, courtesy of a social media ecosystem that’s ubiquitous, barely moderated and well suited to helping aggrieved people find each other.