A traditional protest is characterized by citizens taking to the streets to express their dissatisfaction with something, whether it is a law, injustices, a political figure, a war, etc. Protests happen for only a couple hours at a time, and then people return to their homes and hope that the visibility of the protest convinces political leaders to change something. (Sometimes instead of political change, protesters seek to change ideologies of the population in general.) But essentially, the people put the responsibility for change in the hands of others, not taking direct responsibility themselves.
An occupation is very different, whether the people participating realize it or not. (And not just because of the 24/7 visibility.) In an occupation, the citizens are taking the responsibility for change upon themselves. They're not simply going home at night with faith that the powers that be will listen to them. Occupiers take it upon themselves to make decisions. Camping with strangers 24/7 forces a certain degree of cooperation, and in these recent occupations that often takes the form of a General Assembly, or direct democracy, wherein all major decisions are arrived at collectively. Once the occupiers realize they're able to make collective decisions, the question arises, do we really need the political leaders, economic leaders, or media to make our decisions for us? No, we don't. Regarding the problem we're protesting... why don't we just fix it ourselves? We have the power to fix it ourselves. People participating in direct democracy with a large group of diverse people has a very empowering effect. It sends a message to the powers at be that if they don't fix the problem, the people will fix it for them.
That is why an occupation is much more powerful than traditional protesting, even sustained protesting. And that is why I think the Occupy Wall Street movement has a very good chance of succeeding.