You should start reading up on HIPAA regulations if you will be hosting any of your users' private medical data. This is one of the big reasons that only Googl

You should start reading up on HIPAA regulations if you will be hosting any of your users' private medical data. This is one of the big reasons that only Google and Microsoft are dueling it out over PHR standards--they have major legislative and regulatory affairs departments and fleets of lawyers to make sure they are covered legally. (disclaimer: I'm working on an app in this space)