Possible explanations for the states that swung to Obama ?
AK: probably Palin not being on the ballot anymore, homestate effect in 2008
LA & MS: white people who saw that the black Obama is not the Anti-Christ and that the world still stands after 4 years
MD: liberals turning out for the gay marriage amendment ?
NJ & NY: Sandy and the Osama-got-killed-effect
I think it has more to do with increasing black turnout in both states.
I don't think black turnout really increased compared with the already strong 2008 black turnout.
More like blacks turning out in similar numbers like in 2008, while more whites stayed home or voted for Obama by a slightly higher margin.
IIRC the Black birthrate is higher in the South than the white one which may explain some of this.