Some marketeers are finding out the hard way the difference between a carbon copy (cc) and a blind carbon copy (bcc) when bulk emailing, and it’s a common but potentially dangerous error for those who accidentally get it wrong.

As an HIV clinic in London very recently found out when they sent out their newsletter using the cc rather than the bcc option on their email system. Pasting email addresses into the bcc field usually prevents individual recipients from knowing who else has received the email, so the clinic sent every recipient the email addresses of every other recipient, that is more than 780 patients of the HIV facility. This was a serious error with likely repercussions as sensitive medical information of this kind is sought after by cyber criminals bent on using it for identity theft, or even blackmail. And insurers are increasingly likely to dispute claims arising from the failure of an organisation to protect sensitive patient data.

Less dangerous, but still undesirable from a marketing point of view was the same error made by staff at a London event venue this month where every guest invited to an evening reception was sent an email with the email addresses of all the others, nearly 200 of them. When the error was discovered the venue staff had no choice but to issue an embarrassing apology to their customers and potential customers for the leak. Doubtless some, with services to sell to the others, found the free emailing list of considerable commercial value.