These theories are being spread by people capitalizing on unanswered questions and the heated emotions the American public, and it is sickening (something tells me these are the same people who spread those ridiculous Nostradamus emails right after it happened). Most of these people are not experts - they are every day people looking at photographs and pictures and trying to find elements that would look strange or questionable to a layman. Much of their proof hinges on comments that were made during the disaster, in which news reporters were struggling to give answers. "[insert any famed reporter's name here] said in a RARE report on September 11 that the buildings looked like they'd been blown up...and then they silenced him!" is a familiar story making its rounds. So amazing that we are willing to trust people making off hand remarks in 1) completely disorienting situations, and 2) under intensely heated emotions. And when these sites do later seek experts to explain, say, why the hole in the Pentagon wasn't large enough to accomodate the plane's wingspan, they ignore the multitude of experts who dismiss it for the one or two that agree.

The saddest part about this is that not only is there blame to be placed, but the seriousness of the matter is trivialized by suggesting that not only did the government ignore intelligence, it either aided or directly caused the disaster.

For anyone with any doubt, I'm going to advise you to check out the Popular Mechanics article, which thankfully is the number 1 search result for "9/11 conspiracy". Hell, while we're at it, check out Bad Astronomy's article on why we actually DID land on the moon.

Like I said, SW loves a good conspiracy theory, but not when it's written by imaginative laymen.

-Popular Mechanics: Debunking The 9/11 Myths
-Bad Astronomy: Fox TV and the Apollo Moon Hoax