Deleting information is a bit of a chore

Long before the invention of the PC, mobile phones and the Interwebs, physicist Rolf Landauer showed that a loss of information inevitably results in the dissipation of heat. You should resist the temptation to liken this to the hot air generated in online debate.

The increase in entropy associated with information loss is as fundamental as the conservation of energy in more tangible mechanical and electrical systems. That is, energy can be converted from one form to another, but it cannot be destroyed, and with energy conversion there is an increase in disorder that defines an irreversible arrow of time. Thermodynamics, with its origins in the study of steam engines, is arguably the most robust physical theory ever devised.

Landauer's principle

Half a century following Landauer’s theoretical demonstration, we now have experimental verification of the principle involved. Augsburg physicist Eric Lutz and others have, with a laboratory setup comprising of a single microscopic silica bead held in a light trap created by a laser beam, demonstrated the intimate link between abstract information theory and real-world thermodynamics. In doing so, they have highlighted the physical limit of irreversible computation.

You can destroy information, but only at a cost. Maybe Google will use this as an excuse for not complying with court orders to remove online evidence of Max Mosley’s sexual shenanigans.

Further reading

Bérut et al., “Experimental verification of Landauer’s principle linking information and thermodynamics”, Nature 483, 187 (2012)