The "Occupy" movement is hard to define, there is no real central leadership and no real shared policy. The main complaints are that the rich are rich and the poor are poor - they argue that its unfair that banks are being bailed out whilst the poor are being left without jobs. The main slogan is 'we are the 99%' - that the majority of the wealth is being held by the 1% of the population, whilst the 99% are left with nothing.
I don't see how the movement is going to change anything, but it is global and a lot of people are pissed off about it. The issue is that the majority of the protesters don't understand economics, let alone global economics and can't offer a workable solution they are just pissed off.