Four years on and the tragedy of the September 11 attacks is still raw, writes Ben Rooney. The 911 digital archive, funded by the Smithsonian Institute in Washington, has captured a vast range of material, from video compilations to audio diaries.
The net wouldn't be the same without conspiracy theories - and they don't come better than 9/11. "I know and believe that 9/11 was a controlled demolition," writes Rick Rajter on Hammer Of Truth. "I'm willing to stake my reputation on it." That would be the reputation of a "foosball ninja and ultimate frisbee enthusiast". Big stake.
Many Americans, like Ed Strong, worry that the memory of 9/11 will be used to silence critics. "President Bush and many of his vocal supporters aren't content to wrap themselves in the flag … The ultimate demagogic weapon is to exploit the memory of Sept 11, 2001."
But the most poignant site is the victims site. Each of the 2,996 people killed is remembered on their own tribute page, like that for George Paris, 33, written by his wife. "George, you will always be my soulmate, my angel. I will see you every time I look at our daughter … Rest in peace, my love, we will be together again someday."