Learn to Use That Fax Machine highlights a lawsuit that was triggered by a doctor that faxed confidential information to a fax machine at the patient's place of work. The information fell into the wrong hands, the patient lost his job...and the lawsuit follows.
What's the moral of this story? That people should have the decency not to read other people's faxes (and that there are too many lawsuits, but that's a different discussion). If you don't want to rely upon the kindness of strangers, then you might want to use MyFax...
MyFax provides each customer with their own, private fax number, and delivers all faxes directly into your personal email. This means that all of your received faxes remain private.
MyFax also helps make faxing more confidential. Use your Outlook address book to choose the fax number, and avoid misdialing. Double check the fax confirmation, and make sure it went to the fax number you wanted it to. Automatically add a customized fax cover page.
For secure applications, consider using encryption, or VPN connections for larger customers. That will help meet your HIPPA fax requirements.