For the English-speaking reader, the force of Meillassoux's polemic against correlationism requires some explanation. In order to see what he's getting at, it is necessary to appreciate the way in which French philosophy has been dominated since the 1930s by "les trois H": Hegel, Husserl and Heidegger. The correlationism of Hegel's idealism might appear obvious, but Meillassoux's real target is phenomenology.
Husserl's entire enterprise is based on the idea of a correlation between the intentional acts of consciousness and the objects of those acts, the distinction between what he calls noesis and noema in his later work. Although the intellectualism and Cartesianism of Husserl's phenomenology is heavily criticized by Heidegger, the latter's project of fundamental ontology is also profoundly correlationist. The central proposition of Being and Time is : "Dasein (or the human being) is being-in-the-world". Although the world that Heidegger describes is what he calls "the work world" of everyday things in a practical context, which has led some contemporary pragmalists to find parallels with William James and John Dewey, the world is simply a correlate of Dasein. Without Dasein, there would be no things and no world.
The pervasive influence of Heidegger's critique of Husserl is obvious to anyone familiar with French philosophy from Sartre and Merleau-Ponty through to Levinas and Derrida. But what exactly is the problem with correlationism ? Well, it is twofold. First, by denying thought any rational access to primary qualities or things in themselves, correlationism allows that space to be filled by any number of irrational discourses, such as religion. In a powerful critique of the theological turn in French phenomenology, for example in the work of Jean-Luc Marion, Meillassoux shows how the flip side of correlationism is fideism, that is, the rather vague discourse on the numinous that one finds in many followers of Heidegger, but also - it should be added - in Wittgenstein's curious remarks about the mystical towards the end of the Tractatus. Such is what Meillassoux calls "the religionizing of reason".
I think this also shows a divide between two particular camps of reading Heidegger. Obviously there is a popular American reading (which I know many French don't like) in which the controversial passage about things requiring Dasein is read quite differently without the correlationism and make Heidegger an Ontic Realist.
I haven't read very closely into Meillassoux, the Speculative Realists, and the Deontologistics post I linked to a few days ago, but I have a general sense that there's a nostalgia for Cartesianism and metaphysics driving them all.
We had metaphysics for a couple millenia, then Heidegger opened up ontology again by asking where is being, hidden behind metaphysics? Now, after a few decades, the move is on to hide ontology beind a new metaphysics. I also sense this in Zizek's comment in The Parallax View that even if Heidegger is correct, and there is an ontological difference, it's not much of a difference, so lets set it aside, and get back German Idealism. My sense is that there's still more to understand about ontology and Heidegger's thinking, that the recent metaphysical criticism (e.g. via correlationism in this case) is really shifting the focus away from what is calling for further exploration.