Phone numbers leak more info than you might expect. They tell, based on country and area code, where the caller’s located—or at least where their phone number was registered. The caller’s name is likely to pop up on caller ID, and their carrier may be discoverable with a quick lookup. One could infer that the caller is awake and available at the time of the call. And if the callee answers, one can also infer that they are available—that they heard the call, saw the info, and decided to still tak...