The Economist Blog has a post, Real Robot Talk, which asks what we do when the approaching army of cheap, smart robots makes it not cost-effective to employ the left-hand side of the bell curve.
Suggestions include legislating (in a Luddite manner) to ban such technology, or just accepting that masses of people will never find a productive job .. and simply pay them an entitlement wage - humans as pets.
Of course, as AI programs like IBM's Watson suggest, it's only a matter of time until the right-hand side of the bell curve faces a similar prospect. What on earth are we all going to do then?
I even remember having these discussions in the 1970s as a young marxist, when Ernest Mandel wrote that a society with 100% automation could not be capitalist: no work so no one got paid and there was no demand. Communism via automation not revolution.