I know him fairly well in some ways - his taste in books and music, his sense of humour, his thoughts about human language, his opinions on (some) political issues, and some of his hobbies and interests. I know almost nothing about his personal life, whether he is married or has children, for instance, and I would not want to know anything about such things. I know which country he is from and how long he's lived in my country but that's it as far as background goes.