Leave him a word — publicly, to sit on his map, or privately, just for him.
公开留在地图上，或私下写给他。
Approximate, city-level only — pins are placed near the centre of a visitor's
city, never at an address. No account, no cookie, no IP address is stored.
One home is one pin: returning within a week doesn't count again.
仅显示大致城市位置，绝不精确到街道；不存储任何 IP 地址或个人信息。
同一处访客一周内重复到访不重复计数。