The anti-Wall Street protest in Lower Manhattan entered its third week with hundreds of arrests after the group blocked traffic Saturday on the Brooklyn Bridge, and budding copycat movements across the U.S. continued to stage smaller-scale protests, planning them online on social networking sites.

In New York, the protesters initially set out to occupy Wall Street but were rebuffed by police. Instead, the group set up in a nearby park, keeping the "Occupy Wall Street" moniker. The spread to other cities appears largely organic—the protests don't have a central organizer—and the idea came from a Canadian magazine and grew on social media websites.

Those protesting in New York have been circulating a list of grievances, most of which are aimed at corporations that they say are too powerful and often unethical. Among the complaints: bank executives received "exorbitant" bonuses not long after receiving taxpayer bailouts and companies have "poisoned the food supply through negligence" and "continuously sought to strip employees of the right to negotiate better pay and safer working conditions."

Many of the protesters are young. Joblessness seems to be a persistent theme. A blog that has become popular has pictures of people's faces next to stories of economic woe and messages of support for the protesters.