The Politics of Utopia, Fredric Jameson. New Left Review 25 (2004). Some excerpts and comments:

"It is that utopia is somehow negative; and that it is most authentic when we cannot imagine it. Its function lies not in helping us to imagine a better future but rather in demonstrating our utter incapacity to imagine such a future –our imprisonment in a non-utopian present without historicity or futurity– so as to reveal the ideological closure of the system in which we are somehow trapped and confined." 

He explains the presence or absence of utopias in terms of ideology and fear. He builds on binary oppositions as a way to probe the vast universe of utopias making it clear that this classification has meaning only as it reflects ideological discourses.

"For it will be understood that, taken individually, in isolation from its opposite number, each of these utopian positions cannot but be profoundly ideological. Taken one by one, each term is substantive; its very content reflects a class standpoint which is ideological by definition. <...> But what these utopian oppositions allow us to do is, by way of negation, to grasp the moment of truth of each term."

Bringing examples such as universal employment versus "the right to be lazy", or apolitical versus hyper-political societies, it is worth to mention his comment on the ironic turn in the utopia of planning versus organic growth:

"But today perhaps things stand otherwise, <...> it is nature which has, in late capitalism and the green revolution been subject to careful planning and engineering. <...> As we have known since Polanyi’s classic Great Transformation, the establishment of untrammelled market freedom requires enormous government intervention; and the same can more obviously be affirmed, and by its own admission, for any ecological politics."

Finally he address the issue of the fear of utopia, which he interprets as a fear of alienation where the dialectical field around which our self gravitates fades away with the risk of leaving a vacuum of meaning, an absence of desire ("What would it be for the addict to desire a cure?"). The perhaps over dialectical approach of Jameson describes the attraction and repulsion of utopia as a circular movement, with no particular meaning other than being the engine of history. I still believe he left many important issues aside such as the role of utopia as a precondition for revolutions as opposed to revolts. And about the fears of utopia, it was worth to mention more obvious but direct threats such as the psychological stress of holding a parallel reality which somehow questions our everyday life.