by: Jessica Guynn | Los Angeles Times

SAN FRANCISCO -- In an age of near instant communication, Twitter again became the world's town square as traffic to the service spiked minutes after the deadly Boston Marathon explosions.

People rushed to Twitter for real-time information on fatalities and injuries. It was the first to air the news of the explosions at the finish line (10 minutes ahead of cable news) and to break the news of multiple explosions and mass casualties as users posted firsthand accounts and photographs.