But one cellphone-based service managed to work as normal, according to Bloomberg: RIM's BlackBerry Messenger.
BBM, which can run on either a phone's data connection or local Wi-Fi and uses unique wireless protocols, has gained a reputation for reliability and security. In the Chilean earthquake of 2010, and in the immediate aftermath of 9/11 in New York, it was the only service left standing.
In London earlier this month, BBM was deemed a little too reliable and secure: It was the primary method for rioters to communicate and coordinate. RIM's unwitting role in the riots has come under scrutiny from the UK government.
But on a day when the carriers have all experienced what one Sprint spokesman called "an intermittent mass calling event" and the Department of Homeland Security advised that we not try to call family members on the East Coast, RIM has added a much-needed sheen to its reputation.