What surprised me most about this documentary was the way the relatives of the dead cherished the recordings of those conversations. Several of those interviewed had kept the answerphone messages from their dying husbands, wives and siblings; one had recorded the voicemail message from his brother and kept it on his iPod. Instead of recoiling in horror from the emotion-strewn messages of their loved ones dying (as I expected they would), they were proud and comforted by the sound of their voice.

As well as providing one last opportunity to tell their families that they loved them, the phone calls from the towers were also one of the few pieces of evidence that remain of what actually went on inside The World Trade Center on 9/11. Camera phones barely existed in 2001; social-networking sites such as Facebook and Twitter hadn’t even been created. While the images of the towers collapsing will be indelibly lodged in the memory of all of us, we know little of what actually happened inside the buildings. Those phone calls to relatives help us to picture what happened inside the towers, but most of the images and footage of what happened within were destroyed with the buildings themselves.

Now imagine what it would have been like if Twitter, Facebook and camera phones had been around in 2001. The first many would have heard about the twin towers would have been when Twitter started going crazy with reports of a plane smashing into the North Tower.  Those in the South Tower, or above or below the carnage in the North, might have updated their Facebook status to let friends and family know they were safe, in much the same way that many made those fate-tempting phone calls on September 11.

Then as events unfolded, and it became clear that this wasn’t a freak accident but a co-ordinated attack on several targets across the US, the Twitter rumour mill would have gone into overdrive (providing the notoriously twitchy service could cope with the weight of traffic, of course). Remember that “professional” news channels were spreading unnecessary panic by reporting that everything from the Sears Tower to Canary Wharf were potential terror targets  on that September morning; imagine the maelstrom of confusion and hysteria such speculation would cause when amplified through Twitter.

But what disturbs me most is that within seconds of that first plane crashing into the North Tower, there would have been photos appearing on Twitpic of people both inside and outside the building. We wouldn’t have to paint a mental picture of what events were like inside those towers from the recordings of those phone calls, because thousands of pictures would be appearing online within a matter of seconds. Photos unfiltered by picture editors on news desks; video clips showing people throwing themselves out of the windows that the news channels wouldn’t run.

The phone calls in that Channel 4 documentary, painful as they were, preserved the dignity and memory of the people who lost their lives on September 11. I’m not sure the same would be true of the digital outpouring that would undoubtedly accompany a similar tragedy today.

(Picture taken by Slagheap, used under Creative Commons)