The San Francisco paper today has six pages on the protests. 1400+ arrests. Rob Morse's column describes it best.
It started at 7 a.m. Thursday with an operation as precise as anything staged by the Special Forces. Platoons of protesters arrived simultaneously at various intersections of the city and shut them down.
According to the paper Thousands of people roaming the streets in an organized/chaotic way, hundreds of cops doing battle to control the situation. In Portland in the early 90s when this kind of thing happened the cops went apeshit and started bashing heads. In SF it sounds like the police just calmly did their jobs. Could have been a lot worse.