The theme of Occupy Boston, the tent-city protest in Dewey Square, is hard to pin down. It is like a rolling snowball that collects victims of the Great Recession and those who otherwise feel ignored or disenfranchised.

Joe Gallivan, who is homeless and unemployed, walked past the tents in Dewey Square set up for the Occupy Boston protest. (Bill Greene/Globe Staff) Some of the protesters want to abolish the Federal Reserve. Others demand more housing for veterans. A few admit to being there because it is fun to be part of something big.

The unifying theme, if there is one, is the sense that the voice of the little guy has gone unheard for too long"

"It’s not just a bunch of pot-smoking hippies here,’’ said Hilary Richard, 21, a café barista from Beverly. “These are people who want to make a difference.’’

To be sure, the pot-smoking hippie contingent is represented. Yet so are middle-aged, Izod-wearing Republicans who long for political conciliation in Washington.

“I remember Reagan and Tip O’Neill sitting down and compromising,’’ said Mark Hoffman, 49, a laid-off technology worker, recalling when the president and the speaker of the house hammered out solutions to shore up Social Security in the 1980s. Yesterday was Hoffman’s third day at the protest. He joins the demonstration in the afternoons after class. He is studying at the North Bennet Street School to become a locksmith, a job that cannot be outsourced overseas, he said. The Republican carried a sign that read in part: “Corporations are not people.’’

Three months ago, Mark Joyce-Shore was let go from a low-wage job at a bookstore chain, and it was the best job he could find. Today, “I’m a grumpy 25-year-old,’’ said Joyce-Shore, a protester from Dorchester. “But when I see people come together like this, I’m hopeful.’’

Like many of the protesters occupying the square, he complains about wealth inequity in America and accuses the rich of using their money to influence politics. Two weeks of camping outdoors has given him a bit of a cold, but he declared he will not leave: “We’ll be here until they tase and hog-tie every one of us,’’ he said.

The protest is receiving wide publicity after a police crackdown early yesterday morning. More than 100 protesters were arrested after the demonstration migrated onto a renovated section of the Greenway that city officials had asked them to avoid.

Many protesters complained yesterday that the police were unnecessarily rough.

Another major component of Occupy Boston is the homeless, who have joined the encampment not for political expression, but for food and companionship.

“I’m here because I have no place else to go,’’ said Joe Gallivan, a gravel-voiced former construction worker who erected a cardboard sign near his tent that read: “I’m 54. I’m for hire.’’ He has been homeless, going from shelter to shelter, for three years, he said.

His luck has not improved at the tent city: He lost his cellphone at the encampment, and then his wristwatch broke. “It just ran out of time,’’ he said. But he’s not leaving until the police make him go.

“A lot of people here, they think this is a . . . party,’’ he said. “I’m here because I have a safe haven.’’

Joseph Gubitosi, 43, a homeless man from New York City, wound up at the protest after his recent plans to stay with relatives in Boston fell through, he said. He wore a lapel button that read, “Eat the Rich.’’ He said he has a learning disability and explained: “They were giving these out yesterday. I can’t read, but this is what I picked. People read it for me, and this is what I believe.’’

Ramon Collazo, 24, of Boston has spent 10 days at the protest for a most personal reason: He said he was fired from his store clerk job because he missed too much work when his father was dying. “You should be able to get a leave of absence at a time like that,’’ Collazo said.

Friends had signed Collazo’s tent as they would a high school yearbook. “Peace, love, revolution,’’ read one inscription. Collazo had more immediate thoughts in mind. “Spare a cigarette?’’ he asked a passerby. “God bless you, ma’am.’’

One young woman covered her face with a bandana during a short interview, like a stagecoach robber in a western movie. “I don’t trust anyone anymore,’’ she explained, saying she was among those arrested early yesterday morning. She said the police raid proves that the authorities fear the demonstrators were growing too numerous and powerful. “Why would they arrest a hundred people if they’re not afraid of what we could do?’’ she said. “This is getting bigger and bigger by the day.’’

She said she is protesting to “end corporate control’’ of the government. “People who have money shouldn’t have more of a voice than people who don’t have money,’’ she said, declining to give her name. She said she is 18.

Twenty-year-old Amber Winders just moved to Danvers from the West Coast. She visited the protest yesterday to see what it was all about and spent the day, though she is not pushing a political cause.

“I definitely admire and respect what people are doing here,’’ she said. “It’s super awesome, and I wanted to be part of the experience.’’