Enable Private Me Card in Contacts to selectively share your information
I just found a new(?) feature of OS X’ Contacts.app. In the preferences under vCard is this option: Enable private me card.
When enabled, editing your own vCard allows you to select which information is shared. Very helpful when you have some fax number you want to keep private so nobody will send you faxes, but still be able to keep the number for reference1. *cough*
For instance your insurance company which insists on sending faxes, because they are more secure, they say. ↩