To share their data, users log into Google Health, click on the “Share this Profile” link and type in the email address of the person with whom they want to share information. The person on the receiving end gets an email including a link to the sender’s profile. The receiver can see the profile, but not edit it.

Google has imposed some privacy controls on the data exchange, including a function letting users monitor who has visited the profile. Also, the link contained in the sharing invitation expires after 30 days.

If users want to share their data on paper, Google Health now offers an option for that as well. Upon request, the application prints out a wallet-sized card including the user’s medications and allergies. The PDF, meanwhile, prints a letter-sized copy of the user’s profile listing the patient’s meds, allergies, treatments and conditions.

Neither Google, nor the journalists covering this issue have explained how they’ll handle the issue of emails that end up in the wrong hands, either by deceit or by accident. That, to me, is the big question that needs to be answered here.