Everbridge filled gap in communications By Erin Ailworth GLOBE STAFF Most days, the City of Boston uses mass communication software provided by the global technology company Everbridge for routine reminders and alerts: Move your car for street sweeping; beware of a coming storm; check out the latest senior newsletter. But when two bombs exploded near the Boston Marathon finish line just before 3 p.m. Monday, the software's more sophisticated capabilities became crucial across Boston. The city used the technology to call in additional police and firefighters, mobilize command posts, and direct essential personnel. And companies like Pearson, an education services firm with offices fewer than two blocks from the first blast, used it to check on the safety of employees. "We were anxious to know everyone was safe, and Everbridge gave us that link," said Pearson spokeswoman Wendy Spiegel, "especially since cellphone coverage was spotty during the height of the afternoon." Even as phone lines jammed with an influx of calls from anxious friends and relatives trying to reach their loved ones in Boston on Monday, Everbridge's software was able to bypass overloaded cell towers by using land-based phone lines and Wi-Fi signals to send alerts to phones, e-mail addresses, EVERBRIDGE, Page B7