Does the NSA make the case for a "Beneficent Archivist"?
Between 1660 and 1669, a resident of London, Samuel Pepys, kept a diary. At the time, he was working for the Royal Navy as an administrator and ultimately became one of the most important civil servants of his age.
That diary has become one of the most important historical documents of British history. What makes his diary important (and fascinating) to historians and scholars is that it forms a unique account of day-to-day life of someone who lived through that period.
But it almost didn't happen. Pepys didn't keep his diary with any intention of having historians, scholars, and regular people read it 400 years after he wrote it. He wrote large sections of it in code. Given that it was never intended to be published, someone had to find it, realise its importantce, and then publish it.
If that part hadn't happened, as a global society we would have lost something that aided our understanding of how we developed.
A problem with history is that you never know who's going to be important, famous, or infamous before they are. And when they become so, we generally want to know everything about them.
So doesn't that argue the case for a system whereby we copy everything — every single private and public bit that goes over the internet for every man, woman, and child, in every country — such that future generations can benefit from a total and complete archive of humanity's digital life, just in case we can dig out some sociologically important nuggets?