I remember thinking on 9/11, Those Bastards! They've just given George W a second term! I also remember hoping that there would be a good thorough investigation of the events of the day, since I knew that conspriacy theories would sprout like mushrooms in the days to come.
I have heard them before. I have heard all about how the CIA killed Kennedy, and the Kennedys kille Marilyn Monroe, and a number of notorious dead people are still alive. I once saw a television documentary, meant for children, about Lincoln's assasination, that made it clear that Secretery Stanton was behind it all. (Yes, I know that is extremely unlikely.)
I also have heard about a good many conspiracies, like Watergate. They just couldn't keep that one quiet. Or the coup in Chile, couldn't keep that under wraps. I learned in seventh grade history class that the Spanish didn't blow up the Maine. Conspiracies are tough things to hide. Which is why I am always skeptical when someone talks about a conspiracy.
One of the things that makes me skeptical about 9/11 is the way Bush and Cheney conducted themselves that day. Bush was with a class full of first graders, reading about a goat. He is either a world class actor, or he was genuinely bewildered. He gave us an uninspired speech, then disappeared for the rest of the day. (I suspect he spent much of it worsipping the porcelain god, but never mind.) Dick Cheney was conspicuous by his absence, hiding in a bunker. You'd think, if they knew it was coming they'd make themselves look more heroic.