According to news reports there were several arrests. This would have been at the UN demonstration in the afternoon when several activists entered an intersection as an act of civil disobedience. It was all very quiet.
Bizarrely, the police wouldn't allow cardboard sticks for signs into Zucotti park (everybody knew not to bring wood sticks) because they were painted. But they were OK on the sidewalk, where they might actually have encountered a passer-by.
Just had an interesting conversation with a lady from France in my somewhat halting French. She is a socialist and is sold on the idea of taking action against Assad in Syria, but I guess in France they don't worry so much about getting their government getting them into a ten year war. Very few people here at the hostel are speaking English, and there seems to be a different language at every table. If you aren't a stickler for comfort, I'd recommend you try it out if you stay in New York. Sharing sleeping space and bathrooms is inconvenient, but the place is very pleasant, easy to get to the rest of Manhattan on the subway and feels very secure for someone travelling alone. There is a little cafe with food a little cheaper than the high prices in many places inNew York.