Extortion warnings sent around the US, Canada demanded $20K in bitcoin
                                
                                
                                    (Newser) -
                                    Chaos ensued across the US, Canada, and New Zealand Thursday after schools, businesses, government buildings, media outlets, and other venues were hit with a wave of email threats that warned of bombs going off at each target if $20,000 in bitcoin wasn't paid up,  USA Today  reports. Police...