In July 1987 the Hajj ceremony in Mecca turned into a bloodbath. Shia pilgrims, mostly Iranians, staged a protest, chanting against America, Israel, and Saddam Hussein. Saudi security forces confronted them. Violence erupted. Nearly four hundred people were killed. I was seven years old. My favorite uncle happened to be among the pilgrims that year. In those paleolithic, pre-Internet times we had no way of knowing whether he had survived. Every afternoon state television broadcast updated lists of the identified victims. It took days before all the dead were named and we were able to confirm that my uncle was not among them. Since I left Iran in 2011, that multiday sense of anticipation has settled into a permanent anxiety, a compulsive worry about the safety of loved ones who are hard to reach. Never is this feeling sharper than when the Iranian government shuts down the Internet and imposes a communication blackout. By now those of us who have lived in exile long enough to endure multiple such blackouts have developed what, joking with …