By Craig Timberg
The Washington Post
Five days of harrowing footage from Boston has allowed a voracious nation to experience Monday's bombings and their aftermath almost as the events were happening, with ever-present cameras at once documenting history and pushing it relentlessly forward.
Fueling this situation has been a series of technological shifts that are likely to accelerate in the years ahead as police, corporations and even private citizens gain access to unprecedented troves of video imagery and the tools to analyze them.
Advances in computing power and analytical software have allowed for individuals to be identified and tracked as never before — especially when that information is combined with the location data emitted by most cellphones.
The role of these technologies in the Boston investigation is unclear, but law enforcement experts say that video surveillance and analysis is especially valuable in cases such as this, with an unexpected attack and no obvious suspects at first. The process of winnowing happened with remarkable speed, moving in just days from a mountain of unsorted video, to blurry images of potential suspects, to pictures crisp enough to drive a manhunt.
For those seeking to protect privacy in the digital age, however, the news is not all good. Computer analysis of the faces of those who apply for driver's licenses, passports or entry visas already has created vast databases that some law enforcement officials are eager to use on a routine basis, for what amounts to digitized lineups of tens of millions of people.
The debate over how to balance the needs of investigators with the rights of private citizens remains unsettled. Civil libertarians worry that data gathered for one investigation will inevitably be used for other purposes, allowing a gradual slide into perpetual surveillance of private citizens.
There are so many video cameras operated by so many entities, public and private, that no one has a credible count of how many are in use, though estimates in lower Manhattan alone top 3,000, said Jennifer Lynch, a staff attorney with the Electronic Frontier Foundation.