I was really hoping to be able to pull this all together in an eloquent grand finale, but it's just not working. So rather than keep everyone waiting I'm just going to do this the awkward way:
1. Classical reality is not metaphysical reality. But treating classical reality as if it were metaphysically real is a useful working approximation in day-to-day life. Analogously, what I am about to describe is also not "really" metaphysically real, but is (I believe) a useful working approximation yadda yadda yadda.
2. Likewise, there is every reason to believe that we don't "really" have free will (because free will is not consistent with a deterministic universe, even a quantum one) but the illusion that we have free will is so powerful and the consequences of descending into fatalism so unpleasant that accepting the illusion of free will and living our lives as if it were real seems prudent.
3. Information reproduces in systems that process classical information like DNA, computers and human brains. The reproduction of information obeys the laws of Darwinian evolution.
4. Some of the information that reproduces in our brains is accessible to us on a conscious level in the form of ideas. But our intuitions about what we think we know can be wrong. Not only do we not know what's really going on around us, we don't know that we don't know.
5. Information influences the physical world through a variety of mechanisms. These include 1) the expression of genes as proteins, 2) the control that brains have over the bodies they reside in, including voluntary and autonomic responses, and the placebo effect.
6. Systems of brains can store and process information in ways that is not possible with individual brains. Companies, for example, have "corporate knowledge" that resides in a distributed fashion in the brains of its employees. In a large company no single person has complete knowledge of how all of the processes in the company work. And yet they do. This is one of the great achievements of modern civilization.
7. If individual brains can have memes living inside them of which they are not aware (c.f. point 4 above) then the concepts encoded in a multi-brain system like a corporation (or a religious group, or a political party) might also not be accessible on a conscious level to any of the component brains that contain it. In fact, it is more likely that a concept resident in a multi-brain system be inaccessible consciously because it is further removed from the mechanisms of consciousness than ideas residing in an individual brain.
8. The mega-memes residing in multi-brain systems reproduce according to the laws of Darwinian evolution just like all other information. They also exert physical influences on the world, i.e. these mega-memes have a phenotype. The computer you are using to read this is an example. No one human being knows how to build a modern computer. The mega-meme that created it resides in hundreds if not thousands of brains.
9. We like to think of ourselves as the masters of ideas, that we create ideas to serve our needs. The Great Conspiracy is the hypothesis that ideas -- and in particular mega-memes distributed in large numbers of brains -- are actually using us humans to serve their needs. The internet did not come into being because we chose to build it, it came into being because the Internet is an idea that reproduces extraordinarily well.
10. Not all ideas that reproduce well have consequences that align as nicely with our human aspirations as the Internet. For example, the idea that one ought to have a lot of children is an idea that reproduces well, as is the idea that one ought to adhere to social norms and not question authority. But the consequences of these ideas might not be so benign.
11. The reason that the Great Conspiracy resembles a conspiracy is because mega-memes reside in multiple brains, and the more brains they reside in the more successful they have been and are likely to continue to be. The reason they don't need to expend resources to remain hidden is that they can hide in plain sight. Any brain that realizes what is going on and rebels is simply cast out of the memetic complex (by, for example, the "phenotype" of the adherence-to-social-norms meme).
12. So one of the predictions of this theory is that no one will pay any attention to it, and I will become socially ostracized for advancing it. :-)
Whether or not you buy this, I hope it's a little clearer now why I had such a hard time rendering this idea into words.
BTW, when Dawkins introduced the concept of memes way back in the 1970's he talked about "viral memes" and the kinds of characteristics that a meme might have to reproduce well. For example, the idea that "God will reward you if you spread this idea" reproduces well because it has this "hook". The Great Conspiracy goes one step further and says that mega-memes resident in multiple brains are actually the central driving force in most human activity. Groupthink is not an aberration, but rather the primary dynamic driving the advance (for now) of civilization.