His departure ended nearly 30 years of autocratic rule and provoked euphoria in Cairo, where people climbed onto cars and trucks, waved flags, danced, and cheered. In Philadelphia, Egyptians clung to one another and logged on to Facebook to shout their joy into cyberspace.
Salem, 23, had the news feed from CNN in one ear and the broadcast from Al-Jazeera in the other, even as she fielded nonstop text messages from family in Egypt and phoned every last cousin and aunt.
"I've called every Egyptian in this country that I know," she said. "It's the beginning, God willing, of an amazing, amazing Egypt."
The victory of the protesters was a moment, she said, to savor the joy of life, a moment of faith and family, of long-shot possibility becoming reality. It means everything to her, Salem said, that her parents and grandparents lived to see this day.
And she played a part from 5,700 miles away, standing wrapped in an Egyptian flag during a support-the-protesters rally near Independence Hall on Jan. 31. That was the first of three local demonstrations; the last was a loud, traffic-stopping march through Center City on Feb. 2.
Egyptian students at Drexel, Temple University, and the University of Pennsylvania helped organize rallies through Facebook and other social-networking sites.
"Today Egyptians have achieved the impossible," said Reda, 18, a mechanical-engineering student.
Reda wished he was in Egypt; he has been calling his mother, cousins, and friends there, hearing that the country "is actually changing; people are nicer, even the police."
Not only Egyptians celebrated. When the news broke of Mubarak's resignation, James Hill, 62, sent an e-mail to coworkers at Mondrian Investment Partners, suggesting they meet for lunch at Aya's Cafe, an Egyptian favorite at 21st and Arch Streets. He carried a small Egyptian flag, fashioned from copies printed off the Internet.
"Where did you get it?" asked one of the restaurant owners, Tarek AlBasti, 39. "I'm from Egypt and I don't even have one of these."
Half a world away, Emily Robinson, who worked at Children's Hospital of Philadelphia and now lives in Cairo, was sipping a glass of champagne and dancing with her 14-month-old goddaughter, singing, "The king is gone, the king is done, far, far away!"
"Praise God for the success of the Egyptian people," she wrote in an e-mail.
The United States is home to about 195,000 Egyptians, according to census figures, though the actual figure may be higher.
In Jersey City, where thousands of Egyptians have settled during the last three decades, the people who fill halal butcher and falafel shops were making plans for a celebratory rally.
"The problem is we cannot get anybody from the Police Department to approve it," said Ahmed Shedeed, director of the Islamic Center of Jersey City. "We might just go ahead and do it anyway."
For more than two weeks, he and others have been glued to TV images, ebullient when Mubarak stepped down.
"Unbelievable, they actually were able to remove the stubborn donkey without having to shed any more blood," said Basem Hassan, 36, a doctoral student in New Brunswick.
Shaheen Ayubi, a professor of political science at Rutgers-Camden who interviewed Egyptian President Anwar el-Sadat not long before his assassination in 1981, believes that other protests are unlikely to erupt in the region but that change is inevitable in the Middle East.
"Egypt has been the cornerstone of the Arab world," she said. "People are going to want some sort of change when they see Egypt progressing and moving toward democracy."
Farha Ghannam, an anthropology professor at Swarthmore College who has conducted fieldwork in Egypt for 17 years, noted that the Egyptian army appeared to be in control and that people were comfortable with that. In the United States, military domination of the government would be unthinkable. In Egypt, "the army is considered the force that brings people together, that defends Egypt as a nation; it's invested with all these positive meanings."
Khalil, 31, the chief executive officer of eDealo.me, an online group-buying website based in Cairo, spent the last five months in Egypt before being evacuated.
He and his wife, Jihan Ghanim, 30, travel between here and there for business and family. She had feared the unity among protesters was about to splinter.
"In Cairo, I'd talk to someone riding up in the elevator and get shut down. 'That's enough,' one said. . . . I thought the government was going to win."
The couple plan to return to Egypt in a month, when society presumably will have regained some normalcy.
And beyond that?
"I have a very optimistic view," she said, shrugging off concerns that the Muslim Brotherhood would assume leadership. "This is about the people and not about religion."
Indeed, for many, Friday was a day to celebrate, not to debate.
"I'm going to be living in the moment for now," said Ramy Hassan, 25, an Egyptian American student in Philadelphia. "Tomorrow I'll think about the options that face the Egyptian people."
Contact staff writer Jeff Gammage at 215-854-2415 or firstname.lastname@example.org.
Inquirer staff writers Matt Huston, Mohana Ravindranath, and Daniella Wexler contributed
to this article.