You and I have been through this movie before. The rotating protests are reminiscent of the late sixties, except that then there was one clear focus, the war in Vietnam. This time it's about many things, and no one thing in particular. Hard to guess where it's going to lead, if anywhere.
Swarming rallies convoked by SMS and Internet are a worldwide phenomenon now. Even if the protests were completely ineffective in changing policies, they at least serve as an antidote to severe psychological depression among the millions who are suffering sudden decline in economic possibilities. (See Increasingly in Europe, Suicides ‘by Economic Crisis’ - NYTimes.com.)
Thus the protest rallies are an example of what Gramsci liked to call "optimism of the will". There are other antidotes to depression available: Jihad, neo-Naziism (as in Greece today), religious mysticism, drugs, alcohol etc. Lots of opiates for the people are on the menu. Of all of these possibilities, the big, rapidly assembled protest rallies against perceived injustice, where people of diverse class and ethnic backgrounds discover a common cause, seem to me by far the most healthful, both for the individual and for the society.
Sustained anger and racist hatred are hard on one's health (see Anger Effects on Your Heart: Heart Disease, Atherosclerosis, and More), drugs destroy your physical and emotional defenses, and mystic ecstasy doesn't help much with practical problems. Political protest in an atmosphere of solidarity not only feels better, it may — just may — help bring about a more equitable system.