Sentence:  Now we are liberal with our innermost secrets, spraying them into the public ether with a generosity our forebears could not have imagined. Where we once sent love letters in a sealed envelope, or stuck photographs of our children in a family album, now such <WSD>private</WSD> material is despatched to servers and clouds operated by people we don't know and will never meet. 
Meaning of the word marked with <WSD> tags:  Belonging to, concerning, or accessible only to an individual person or a specific group.