From the consumer's point of view, Microsoft's HealthVault site is part library, part filing cabinet and part fax machine for an individual or family's medical records and notes.
The free site is tied to a health information search engine the software company launched at the end of last month. It gives users a repository for health-related data such as medical histories, immunizations and records from the doctor's office and hospital visits as well as measurements from devices such as heart rate monitors.
Users can dole out access -- in the form of e-mailed invitations -- to different slices of their private health data to doctors, family members and other people they trust as the need arises.
The HealthVault site itself doesn't do much more than provide a window into stored information and a mechanism for sharing it. Microsoft hopes hospitals, doctors' offices, advocacy groups and insurance companies will build Web applications that patients will want to use.
Microsoft said applications from the American Heart Association, American Lung Association and other organizations are in the works, and devices including blood glucose monitoring systems made by Johnson & Johnson will be able to upload data into the system.
Microsoft said CapMed, which markets personal health
Microsoft said it plans to support HealthVault with advertising revenue from the search portion of the site.
Sean Nolan, chief architect of the company's two-year-old Health Solutions group, characterized the "beta" launch of HealthVault as an early step into a difficult industry.
For one thing, 80 percent to 85 percent of doctors in private practice don't keep electronic records, and hospitals aren't much better, according to Lynne Dunbrack, program director of market research group Health Industry Insights. And where electronic records do exist, there's no guarantee that any two health care providers will call the same treatment or lab work by the same name.
When it comes to business technology, health care is "where other industries were in the 1980s," Dunbrack said.
And some of the best sources of comprehensive health records data -- major insurance providers, many of which offer personal health records tools -- haven't agreed to build applications that work with HealthVault.
Those insurance companies have been "the toughest nut for us to crack," said Nolan.
Even if Microsoft were able to get providers and insurance companies to feed data into HealthVault, it's not clear consumers will want to access it over the Web.
Dunbrack said consumers don't seem to know that insurance companies and some employers already offer some form of personal health records.
And though consumers have been willing to send financial details over the Web despite identity-theft horror stories, they remain concerned about privacy.
"Consumers want to have control over what gets into the record, what data persists that would then be available and could be shared with other providers," she said.
Microsoft's Nolan said gaining consumers' trust is a potential problem, one the company tried to address by spelling out exactly what data would be shared each time the user connects to a new application or gives someone new permission to see a record.