An essay by Bruce Schneier on BBC.com:
Welcome to the future, where everything about you is saved. A future where your actions are recorded, your movements are tracked, and your conversations are no longer ephemeral. A future brought to you not by some 1984-like dystopia, but by the natural tendencies of computers to produce data.
Data is the pollution of the information age. It’s a natural by-product of every computer-mediated interaction. It stays around forever, unless it’s disposed of. It is valuable when reused, but it must be done carefully. Otherwise, its after-effects are toxic.
The essay goes on to cite specific examples, though they sound more high-tech than the actual problem. Later it returns to the important part:
Cardinal Richelieu famously said: “If one would give me six lines written by the hand of the most honest man, I would find something in them to have him hanged.” When all your words and actions can be saved for later examination, different rules have to apply.
Society works precisely because conversation is ephemeral; because people forget, and because people don’t have to justify every word they utter.
Conversation is not the same thing as correspondence. Words uttered in haste over morning coffee, whether spoken in a coffee shop or thumbed on a BlackBerry, are not official correspondence.
And an earlier paragraph that highlights why I talk about privacy on this site:
And just as 100 years ago people ignored pollution in our rush to build the Industrial Age, today we’re ignoring data in our rush to build the Information Age.