Moore visited Liberty Plaza Park, formerly known as Zuccotti Park, in New York's financial district Monday evening to shout approval to the activists after they marched through the district that houses many major financial institutions, including the New York Stock Exchange and the Federal Reserve Bank of New York.
They have used the park near the World Trade Center site as a campground and staging area for their actions since Sept. 17.
"I am honored to be in your presence," Moore told several hundred people in the park, saying each of them represented thousands of other Americans.
"One-hundred years from now people will remember that you came down to this plaza and started this movement," Suite101.com reported Moore as saying.
Activist Noam Chomsky endorsed the Wall Street movement Monday, praising protesters for what he called their "courageous and honorable" action and announcing his solidarity with them.
The protesters are demanding changes to U.S. social and economic policies they say unfairly favor the rich. A group called the 99 Percent said its members would "no longer tolerate the greed and corruption of the 1 percent."
The demonstration was peaceful Monday and police reported no arrests.
This contrasted with Saturday, when police made 87 arrests during a march north about 3 miles from the financial district to Union Square, a large public square off Broadway. A senior officer identified by New York police as Deputy Inspector Anthony Bologna, a longtime commander, was shown on YouTube videos using pepper spray on peaceful female protesters.
Police chief spokesman Paul Browne defended the pepper spray use as appropriate and added it was "used sparingly." But Peter Vallone Jr., chairman of the City Council's Public Safety Committee, told The New York Times that in the video clips he had seen, the use of pepper spray "didn't look good."
Officers are allowed to use pepper spray under certain conditions, including "when a member reasonably believes it is necessary to effect an arrest of a resisting suspect," the police department's patrol guide states.
The spray should "not be used in situations that do not require the use of physical force," the guide states.
Demonstrators said they planned to continue protests Tuesday, and demonstrations were planned in other U.S. cities too, including San Francisco, Los Angeles, Denver, Minneapolis, Chicago and Boston, a new nationwide activism coalition said.
The New Bottom Line coalition claims to represent "more than 1,000 faith-based and community organizations that seek to hold Wall Street accountable and find solutions for struggling and middle-class families."
Its Web site identified about three-dozen such organizations, a United Press International review indicated. The group did not immediately respond to a UPI e-mail seeking more information.
The New York activists may be evicted from Liberty Plaza Park, owned by commercial real estate company Brookfield Office Properties Inc., WNBC-TV, New York, reported.
Signs have gone up saying that the 33,000-square-foot park is meant for the general public's "passive recreation" and that camping, tents and sleeping bags are prohibited.
The TV station reported unidentified "men in suits" handed out leaflets with similar warnings.
Brookfield told the station the protesters could be "legally ordered off the park in the next day or two."
Protesters told the station they'd heard the warning for 10 days.