I recently received an e-mail from a reader of this site saying “Privacy is gone. Thank you for your efforts to preserve it.”
Kind words, and I thanked the writer.
However, the writer’s e-mail “signature” included the his/her full name, mailing address, phone and cell numbers. Given all this personal information, it probably wouldn’t take much to get a complete record of the writer’s cellphone activity, or even social security number.