Often crazy delusions get branded as conspiracy theory's (Eg. Soul collectors on the moon). These are clearly false to anyone with a rational mind, I would rank a faked moon landing theory among these due to the reflectors left on the moon mainly by those landings.
There are other ones which have some element of truth in the 9/11 theorys etc. but have been blown way out of proportion, sure it's clear that some people knew something big was going to happen by activity on the stock market. But does that shown it was all planned internaly? or does a few seconds of grainy video "prove" anything when it's enlarged so much an entire pixel fills 1/4 of the screen.
Others however are almost completely true, Watergate for example or the secret summer get together's of the rich and powerful been mighty strange (although nothing illegal).
To me its pretty clear that the world is full of pretty dodgey deals and corruption but I don't think that it's an organized effort to delude everyone just lots of little pockets of filth.