Eh, the only people to really enslave anyone was the mer (dunmer, alyeids, and arguably the altmer). So do not expect the nords to have slaves (in fact, men in general do not like slavery)
As for how they live, you must remember that Skyrim isn't a unified country, much like ancient Greece. Each city is its own state, with some forging alliances, and hating the others. In fact, the way the country is ran is a lot like ancient Greece; a loose confederation of city states, most likely ran by a tyrant (not the negative connotation kind).
Remember, nords =/= norse, despite the similarities.
there weren't any slaves in solstheim, but there weren't any people to really enslave.
we don't know a whole lot about nords, except what we saw in solstheim and bruma, so i drew on norse similarites as speculation. (never played tes I or II)
im hoping for a slightly darker game than oblivion, but not as dark as morrowind, and would like to see a faction or warband that enslaves bosmer. i wouldn't be upset at all if there weren't slaves, because there are no indications that nords enslave anyone.