[rudasn]

If users upload their medical info themselves I think you can side step these concerns - you still have others, handling and storing this type of data.

So one area to focus on is making it super easy for patients to obtain their data in electronic form, and parsing that data into a common/shared schema (like hl7 or fhir) to make it workable.

Once the data is there, you can focus on "social" features like inviting others to view all or some of your data and be able to leave comments/make annotations. Less focus on who the other user is, more on how effortless would be for them to navigate through the data, take notes, generate a report.

Then you dont need to worry about issues related to marketplaces, like bringing the providers onboard first, as patients will be pulling them in as needed via simple invite links.

Patients could also make their data public for experts to navigate, compare, or examine. This is where the magic occurs, if you manage to figure out the User Experience doctors need to make full use of all the data and tools you give them.