Second time I have disagreed with Leslie, but I use email all the time. I find it to be very secure save sending it to the wrong person.
I would much rather answer an email question than have to talk on the phone, and eventually it will be much more reimbursable.
As far as confidentiality, there is a very detailed section of HIPAA on how to do it. It involves a couple of emails to receive permission. You can then talk about HIV if you want, again making sure not to send it to the wrong person.
Certified Mail, which I used for a long time (changed name but can still Google it) is awesome. I only stopped using it because doctors over 45 couldn't understand how to write in one password. This is all changing as all graduating medical students have iPods, Smart Phones, etc.
Everything is moving toward patient portals, but the cost is a big factor.
