What if the attacks of September 11 had occurred in the era of YouTube, Twitter, Facebook, and the cell-phone camera--none of which existed back in 2001?

Here is my column on that topic from tomorrow's Wall Street Journal, "9/11, Through a Digital Prism": adapted from the new preface to Watching the World Change, which is being reissued this month to coincide with the tenth anniversary commemoration.

President Obama, in today’s radio address, discusses the twin impulses of unity and compassion that Americans exhibited in the months after the 9/11 attacks a decade ago: “Even the smallest act of service, the simplest act of kindness, is a way to honor those we lost, a way to reclaim that spirit of unity that followed 9/11…. We were united, and the outpouring of generosity and compassion reminded us that in times of challenge, we Americans move forward together, as one people."

I sense this spirit in the air, in fact, as Hurricane Irene approaches the city and neighbors and friends reach out to one another.

...9/11 DOCUMENTARY TO BE RE-BROADCAST. On Sunday night, September 11, 2011, CBS will air an updated version of our Emmy-winning documentary, 9/11, to be hosted again by Robert DeNiro. The special two-hour program, created by Jules and Gedeon Naudet, with James Hanlon, and CBS's team, headed by Susan Zirinsky, will examine what has happened to the firefighters of Engine 7, Ladder 1, providing a first glimpse inside the 9/11 Memorial Center.

ALSO… I'd like to point out a new work of revelatory scholarship and insight by Greg Mitchell that will speak to all of those concerned about the lessons of the nuclear age: Atomic Cover-Up: Two U.S. Soldiers, Hiroshima & Nagasaki, and The Greatest Movie Never Made.

The New York Post has an inspirational article today by Leonard Greene ("WTC's Place of Peace,") about the 9/11 Memorial Plaza. In the story, Matthew Donham, a partner in the architectural firm that helped with the design, remarks about the twin reflecting pools: "We describe these as voids. The idea was to make an absence that was visible."

Also explained: visitors will be able to search the nearly 3,000 names of the deceased ("etched in bronze on the memorial pools and illuminated in a soothing light") by using a special iPhone app created for that purpose.

Please be on the look-out for three new books. All contain prefaces written by yours truly...

--John Loengard's Age of Silver (PowerHouse), examining master photographers and their work as the era of traditional film reaches its twilight.

--Questions Without Answers (Phaidon), showcasing the ten-year history of the vaunted VII photo agency, founded September 9, 2001.

--The newly reissued Watching the World Change: The Stories Behind the Images of 9/11 (Picador), with a preface on the roles that image and social media have played in documenting news events since 9/11.

...ALSO... The San Francisco Opera, on September 10, premieres Heart of a Soldier, the tale of Rick Rescorla (described in James Stewart's masterful biography and in Watching the World Change), the decorated Vietnam veteran (and singer of rousing tunes from his native Scotland), whose planning, security drills, patience, and sheer spirit saved hundreds of lives on September 11, 2001. Here's Joshua Kosman, of the San Francisco Chronicle on the subject.

As we begin to commemorate those who were lost on September 11, one could do worse than to:

...Watch the trailer for Jim Whitaker’s powerful new 9/11 film, Rebirth (which he produced as part of Project Rebirth) and to attend a nearby screening, if so moved.

...Settle in and browse the new audio archive (Voices of 9.11) associated with the most comprehensive and powerful archive of 9/11 imagery, “here is new york.”

CBS announced that on the weekend of the 10th anniversary of the September 11 attacks, the network will rebroadcast "9/11," the documentary (hosted by Robert DeNiro) that examines the lives of a group of firefighters in a single firehouse on that fateful day. Shot by the French filmmaker-brothers Gedeon and Jules Naudet, with the assistance of firefighter-producer-actor James Hanlon, the documentary has aired in 140 countries.

The Naudet brothers, Hanlon, Susan Zirinsky, Graydon Carter, and yours truly won Emmy and Peabody awards as executive producers of the documentary.

The Naudets' story is told exclusively in Watching the World Change: The Stories Behind the Images of 9/11. The book is being republished later this month -- with a new preface that addresses the advances since 9/11 in social media, digital photography, and 24/7 news, considering how these breakthroughs have propelled and shaped political change.