When Mark Permann slipped on his Polar S610 heart monitor for a morning run across the Brooklyn Bridge on Sept. 11, 2001, the watchlike device recorded more than the beating of his heart.

A chart created from the monitor's data shows Permann's heart rate spiking when he heard and saw airplanes hit the World Trade Center.

"The fact that you sort of see the planes hitting in my heart rate, I thought was just kind of amazing," says Permann of New York's Upper East Side. "This is a picture of what was going on inside someone's body."

After sharing the chart with friends, Permann, now 36, uploaded the image to the September 11 Digital Archive in August 2002.

Permann's heart rate chart is one of more than 150,000 pieces of history uploaded to the Digital Archive, an online collection of photos, stories, e-mails, video clips and animations. The pioneer project is collecting history not through traditional oral interviews and written documents but with bits and bytes.

"We've ended up collecting things that are more of a private nature, things you'd find not so much on the Web but on people's hard drives," says Tom Scheinfeldt, assistant director of the Center for History and New Media at George Mason University in Fairfax, Va.

The still-growing archive launched in January 2002 with the aim of collecting 1,000 stories. By September 2002, 90,000 stories, photos and other artifacts, such as Permann's heart rate, were submitted.

Researchers believe the variety of testimony and individual stories could ultimately make history more democratic, Scheinfeldt says.

"I think for the history of 9/11 and the history of (Hurricane) Katrina, I think it's much less going to be the history of George Bush's experience of 9/11 and much more the experience of you and me," he says.

Other digital history projects, made up mostly of text and photos, have asked the public to upload memories of World War II (bbc.co.uk/ww2peopleswar) and the first Macintosh computer (folklore.org).

"I do think that digital media has transformed to some great extent the future of what collecting, archiving and documenting a historical event is all about," says Josh Brown, executive director of the American Social History Project at City University of New York and a co-executive producer of the Sept. 11 archive.

Brendan Chellis, a computer server engineer at Empire Blue Cross Blue Shield on the 30th floor of the World Trade Center One, was walking toward the building when the glass revolving doors shattered from the impact of the first plane. He ran into the chaos of Lower Manhattan and finally returned home to Roosevelt Island about seven hours later.

That night, he wrote a long e-mail and sent it to family and friends, who forwarded his message to more people. He got e-mails back from people he didn't know. Chellis saved the e-mails and a 4,800-word narrative he wrote about two months later. He uploaded the story to the Digital Archive in July 2002.

"I wrote it for myself and for close relatives, close friends," says Chellis, 40. "I really wanted people to know what it was like to be there."

Creators from George Mason and the City University of New York partnered with the Sonic Memorial Project, an audio database, and took content donations from other collections. In 2003, the Library of Congress acquired the contents of the September 11 Digital Archive to add to its 9/11 collection.

Jan Ramirez, chief curator and director of collections at the World Trade Center Memorial Museum, considers the Digital Archive itself part of the history of Sept. 11.