Global digital information amounted to 281 billion gigabytes in 2007, or almost 45 GB of digital information for every person on earth, according to research by analyst IDC.

The figure is 10 per cent more than the previous estimate, and is expected to hit 1.8 zettabytes (1,800 exabytes) in 2011.

In graphical terms, IDC describes the digital universe to be the equivalent of over 17 billion iPhones with eight GB memory

IDC notes that the digital universe has a compound annual growth rate of about 60 per cent, thanks to a jump in worldwide shipments of digital cameras and televisions, as well as better understanding of information replication trends.

Increasing internet access in developing nations, sensor-based applications and extensive online social networks have also contributed to the growth of digital information worldwide.

"For the first time, your digital shadow is larger than the digital information you actively create about yourself, such as taking pictures, sending e-mails, or making digital phone calls" says John Gantz, IDC's chief research officer and senior vice president.

Gantz said the digital shadow is information about a person, including names in financial records and mailing lists, web surfing histories or images of the individual taken by security cameras in public places.

IDC notes that to deal with the digital explosion, development of organisation-wide policies to ensure information security and retention, as well as data access, is essential.

The IDC study also reveals that enterprise the amoun of data collected is industry specifis, with little relationship to GDP or IT spending. For example, the finance industry accounts for almost 20 per cent of global IT spending, but only six per cent of the digital universe.

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