[rsync]

"I loved the anecdote on the Jewish census. Because I am always struggling to find examples about why sharing information might not be dangerous now, but it can be later, and you never really now."

The best example of this is the handwritten notes of the Tsars Russian imperial intel/police services in the very late 19th and early 20th centuries.

Handwritten records and notes stored in shacks that were retrieved and indexed around (forgive hazy dates) 1905 and used to track down "revolutionaries".