For centuries, we'vebelieved life holds only two certainties, death and taxes. Get ready for number three: sooner or later, everything goes digital.

Proof of this new certainty comes from Anoto, a Swedish start-up that has developed a digital version of an ancient product - paper. Digital paper looks and feels like ordinary paper - it even makes the same noise as ordinary paper if you scrunch it into a ball. But, if you hold digital paper next to paper from a printer or a photocopier, you'll notice it looks grey.