Whats the difference between socialism and dictatorship?

They are not remotely related. Dictators tend to serve for as long as they are alive, and with absolute or near absolute authority. Since Obama only has 6.5 years to go, and clearly does not have unchecked power (he would be accomplishing far more if he did), it is silly to call him a dictator. Pretty much just like it is silly to call him a socialist. He is a moderate.