The British Library estimates that it costs half as much to store a digital document as it does a physical one.

ECONOMIST: Archiving the web

Increasingly, individuals, organisations and communities are using digital technologies to document and express what they value and what they want to pass on to future generations.

UNESCO: Communication and Information

The Twitter archive might be its biggest and most challenging effort, but it's not the first time the Library of Congress has sought to document the digital world.

CNN: Library of Congress digs into 170 billion tweets

Officials said they made digital radiographs and computer scans to document the internal condition of the battery before taking it apart.

CNN: STORY HIGHLIGHTS

For instance, before the bank issues a certificate, the bank snail-mails a document containing unique information the customer must use to activate the digital certificate.

CNN: Technology - E-Signature Act may drive demand for authentication technology