With cellular service unavailable in Boston, the best way -- and perhaps the only way at the moment -- to communicate with friends or loved ones may be through an Internet-connected service.
Boston's cellular lines are either jammed with traffic or have been reportedly shut off to prevent a device potentially triggering an explosive. You can still reach those in the city, however, if they are connected to a Wi-Fi network.
Facebook and Twitter are being used to reach out to those in the city. You can either message the people you are trying to reach or simply check to see if they have already gone online to update their status. The user below, for example, used Twitter to alert her loved ones that she's safe.
Hey everyone, I'm ok, safe in Cambridge. Heartbroken and horrified about the explosions at Boston Marathon.
-- Nilagia McCoy (@nilagia) April 15, 2013
You can also try finding people by going to a couple of websites.
The Red Cross' SafeAndWell.org is a website that is used to connect people during disasters and other emergency situations. Right now the site is having difficult loading, but the Red Cross advises users to keep trying.