HealthVault is a free online service that stores your health records in a central location, then lets you use the information with online health tools to manage health conditions, create fitness plans, prepare for doctor visits, and more.
An interesting concept about keeping track of all your medical conditions and what not in one spot - online. Safe from fires and disasters. I could see this being quite helpful, but at the same time quite concerning about having that information mined.
At least their privacy statement is positive:
Microsoft won’t use your information in HealthVault to personalize ads or services without explicit permission.