We are all already regulated, already participants in networks of power, already constituted within the operations of power -- and notions such as the "free individual," on whom power descends from above -- are completely meaningless. Foucault did not believe that this position entailed "seeing power everywhere" or reducing everything to power, just as Marxism had reduced everything to economics, although this criticism is frequently made of his work. He suggested instead that the problem was to understand how power operated in specific methods and strategies, how major shifts such as the increased disciplining of individuals in modern western society had taken place, and how one could show the political and economic dimensions of changes in power.
People don't always interpret things in the same way, and I think this is the point post-modernism wants to make. It is certainly appropriate to make this point, especially when responding to someone who insists that their interpretation is the only interpretation!
But it seems to me that the impulse to "deconstruct" comes too late. Only when you have a community of intellectuals invested in "modernism" can you arrive at a place where you "need" a community of intellectuals invested in "post-modernism." And that's because, had anybody bothered to think for themselves in the first place, the "constructions" which exclude certain perspectives (those excluded from the professions at that time) would never evolve into "deconstructions" which exclude others (those excluded from the professions now), because there was never any justification for them in the first place. Maybe I am missing something, but this seems to be lost on professionals, and people who want to become professionals, if not surprisingly.
This is what David Harvey is getting at when he says he doesn't read Foucault as "anti-Marxist." And that's because you don't have to. You can read Marx, or anybody else, in whatever way you want. If you place a determination on Marx that Marx is deterministic, that is fine, but nobody else has to. They will take from Marx what is relevant to them -- and you can keep your determinism, if that is what is most useful to you; if that is the extent of what you want to take from Marx, and helps you get along in the world, achieve your goals, and so on.
It was only after I was two-thirds of the way through the above book that I realized that the "Marxism [that] had reduced everything to economics" was the Marxism of the 20th-century, socialist state. But, as Foucault himself would point out, that is not the Marxism of either the 19th or the early 21st centuries. So we have to remember that people in different circumstances interpret things in different ways, and we have to remember this in the first instance -- not only after the professional climate has changed.