The strategy, as in New York, is to have people stay for days, in hopes of influencing changes in policies and laws that supposedly favor the rich.
Before 9 a.m., the scheduled starting time, more than 20 police officers and their bicycles were assembled under the Frank Rizzo statue across from City Hall, preparing to help keep the peace.
Protestors were arriving at Dilworth Plaza with such signs "HUMAN NEED NOT CORPORATE GREED," carried by Calvin Morrison, 20, a Temple education student from Willow Grove.
By 10:30 a.m., several hundred demonstrators had gathered, and an impromptu jam session erupted among several musicians, including guitars, a trumpet and drums.
Other signs said: "This is class warfare, and we're losing" and "Greed can't pay my bills."
Periodically, someone would stand on a concrete wall to make an announcement, such as to tell the crowd where to find event organizers.
Those announcements were repeated loudly by others in the crowd so that those in back could hear, as has been the format for announcements in the New York City demonstration.
Police Commissioner Charles H. Ramsey walked along the perimeter of the protest, shaking hands with demonstrators and listening to their stories.
The police presence was unobtrusive, with handfuls of officers scattered around the edges of the demonstration.
As the morning wore on, the crowd started to chant "We are the 99 percent," the protest's rallying cry.
Walker, of Northern Liberties, held aloft a sign reading, "Is democracy already dead, or is it down for the last count?" She described herself as a child of the Sixties, and said she protested the Vietnam War.
"I'm so proud of the young people today, because they are awake," she said.
Mike Fox, 27, of Haddon Heights, who recently finished a seven-year hitch in the Army, explained the Guy Fawkes mask on the back of his head, saying it represented "Anonymous" - a name used by activists behind the recent uprising in Egypt.
Around noon, a woman led a small yoga class a little ways away from the center of the protest. Businessmen and women began passing through the square for lunch hour. As one elderly man in a suit walked by a group of young adults sitting on the steps, he said, "Just make sure you vote next year."
Three Drexel law students leaned against a wall with signs, chatting with passersby. Steve Budd, 23, said he was protesting corporate spending and the growing wealth disparity. "All movements start with someone standing up," he said. "With the wealth gap, we don't necessarily know how to fix it, but we know something's wrong."
His friend, Tom Kelly, said he has differences with many of the protestors, but was frustrated by a lack of jobs and opportunities for members of his generation. Kelly works three part time jobs while going to law school.
"Our generation is going to have to define itself as the hustle generation," he said. "We don't have a choice. The work isn't there. I worked hard, I got good grades, and I'm working part time because no one will hire me."
Kelly was pleased to see so many professionals and retirees along with students in the crowd.
"I don't want this to come off as some group of shiftless youth, or unemployed adults," he said. "These people have jobs. They're just like anyone you see on the street."
The earliest arrivals outside City Hall today were volunteer "medics," who planned to help in a variety of ways, from first aid to counseling to referring people to medical professionals, according to Xio Martin, 39, an unemployed mother from South Philadelphia.
Contact staff writer Peter Mucha at 215-854-4342 or firstname.lastname@example.org.