Barack Obama is not a big-S Socialist. He does not buy into the tenets of those true historical socialists. I don't think he's attempting to wrest control of the means of production away from the bourgeoisie and into the hungry hands of the proletariat. (Quite the contrary, I'm of the Carney School that he's redistributing wealth into the hands of big corporations.)
However, that hasn't and shouldn't stop proper descriptions of Obama's policies as socialist. In two major areas of Obama policy you could properly describe what his Administration has undertaken as "socialization of risk." He believes that the government should be tasked with luck redistribution. Thus he thinks that healthy people should pay above-market rate for health insurance to compensate for those with pre-existing conditions, and that the federal government should bail out institutions and homeowners who took overly-risky positions in their financial transactions.
To a large extent socialized risk is a mainstay in American society. It is but fringe movements that wish to do away completely with federal deposit insurance and welfare and other forms of last-resort-government backstops.
The Obama administration has been pursuing an increase in socialization of risk rather than trying to increase responsibility. There's no clean way to do this, of course, but it is clear that Obama is moving toward a more socialist risk system than to one that emphasized individuality and responsibility, or at least tried to more clearly delineate between bad luck and irresponsible behavior.
Does this make Obama a "socialist"? No. But he should not be immune to the charge.