Jan. 20: Tens of thousands of people crowd the National Mall in Washington, D.C. hours ahead of Barack Obama's presidential inauguration.
The preferred way to communicate if you're in the Inauguration Day crowd: text messaging.
Did you go to President-elect Barack Obama's inauguration in person? Congratulations, and more power to you.
Did you call a friend or e-mail photos from your cell phone during the swearing-in? You might have helped strain the wireless networks.
"I had to stand in the same place for 20 minutes just to have a conversation with my mother," Christian Kingston, an 18-year-old college student who was among an estimated 2 million people jamming the streets and the National Mall, told the Associated Press.
All four major cellular carriers — Verizon Wireless, AT&T Wireless, Sprint Nextel and T-Mobile — had spent millions of dollars trucking in temporary cell-phone towers to Washington, D.C., to handle the huge strain inauguration attendees were expected to put on their networks.
Kingston said his carrier was AT&T, and that some text messages had been arriving an hour after they'd been sent.
"It could be the busiest day that anyone has ever seen," Verizon Wireless spokesman John Johnson told the Boston Herald.
National Mall personnel told FoxNews.com that some cellular service was already down in the area at 8 a.m. on Inauguration Day, four hours before the official ceremony, but was restored about an hour later.
New Yorker Bernice Salik, another AT&T customer, told the AP she couldn't get through to her sister who was also in Washington, but had successfully called her husband back home.
"It seems like people are having a hard time reaching other people in Washington," said Salik.
AT&T and T-Mobile reported congestion at some towers and said they were shunting service to less-trafficked ones. Verizon said most of its calls were getting through, despite three to five times the normal volume of calls.
"Companies are going to extraordinary lengths investing significant amounts of time and money, and are doing everything within their power to boost network capacities in Washington, D.C. for this historic event," said Steve Largent, president and CEO of CTIA-The Wireless Association in a press release last week.
For that reason, says Largent, please don't call if you're on the Mall — text instead.
"Think of a wireless network like a highway," said Largent. "If millions of people jump on the road at the same time, there could be a traffic jam. ... We want to remind Inaugural event attendees to do their part in decreasing network demand by texting instead of placing voice calls, and holding off on sending cell-phone pictures or video until after the events are over."
Text messages basically ride in the otherwise little-used communications space set aside for technicians in each and every "ping" your cell phone sends to the nearest tower to let it know it's there.
So sending texts, which are limited to 140 characters, a minuscule amount of data, shouldn't snarl traffic appreciably. (They also don't cost the service carriers anything, which raises the question of why you should have to pay for them at all, but that's another story.)
It may not have helped that news media organizations, including FoxNews.com, asked people to send in their photos, videos and personal accounts of being on the Mall as Obama was sworn in.
"We can only bend the laws of physics so much," CTIA spokesman Joe Farren told CNET. "If there are 4 million people on the mall streaming video, sending pictures or calling, there could be congestion."