HealthVault lets you share your "strong" password with other providers of your choice, but what happens when you move or don't want to see that provider anymore? Do you have to change your password everytime?Think of how Facebook does it. You put in a whole lot of personal information and choose to privatize it so only your friends have access. This way, anyone outside your friend circle sees very basic information when looking you up. They can "add" you as their friend, but you have to give them permission first. It keeps things secure and private.
Similarly, you could create your "health profile" in HealthVault and "add" or "remove" doctors or they could request to be added or removed. Also, you could restrict how much content can be viewed based on who is looking at your profile; insurer, employer, provider, etc. The patient is empowered and the doctor is informed. Simple and secure. Maybe Google is up to something like this!?