Daly Barnett, EFF:
“Doxxing” is an eerie, cyber-sounding term that gets thrown around more and more these days, but what exactly does it mean? Simply put, it’s when a person or other entity exposes information about you, publicly available or secret, for the purpose of causing harm. It might be information you intended to keep secret, like your personal address or legal name. Often it is publicly available data that can be readily found online with just a bit of digging, like your phone number or workplace address.
By itself, being doxxed can be dangerous, as it may reveal information about you that could harm you if it were publicly known. More often it is used to escalate to greater harm such as mass online harassment, in-person violence, or targeting other members of your community. Your political beliefs or status as a member of a marginalized community can amplify these threats.
Although you aren’t always faced with the option, taking control of your data and considering precautionary steps to advance your personal security are best done before you’re threatened with a potential doxxing. Privacy does not work retroactively. A great place to start is to develop your personal threat model. After you’ve done that, you can take specific measures to advance your data hygiene.