Cheney and his cronies used fabricated data and intimidation to push their agenda in favor of an invasion of Iraq. All the blood and all the treasure wasted on this so-called "War on Terror" came about because powerful men decided to create a phony story linking Saddam to 9/11.
"Never Forget!" exclaimed the bumper stickers of their supporters, even as they rapidly forgot the war against al Quaeda in order to push an ill-advised and worse-executed grab of Iraq's oil fields.
Waves of fruitcakes are using the 9/11 attacks to push various conspiracy theories about who was "really" behind the attacks. The CIA or the Mossad or some other shadowy group is supposed to have planted explosives to bring the towers down. No amount of debunking will ever be enough for these nut jobs, though several people have tried:
Screw Loose Change
Debunking 911
Debunking the 9/11 Myths: Special Report
I wish that people could accept the attacks for what they were: An atrocity motivated by the hatred of a few extremists. One of the ironies of the attack is the way it has been used by other extremists to justify actions and attitudes that look an awful lot like those found among the attackers.