RHIO stands for Regional Health Information Organization. Its a mouthful for an initiative that local and state governments are working on to make your health information more accessible. Just like email, it'd be nice if you could view your medical records from anywhere; recent doctor visits, prescriptions, maybe your lab work. It'd be even nicer if a doctor could see your medical records, say if you hurt your leg hiking far away from home and were allergic to a certain anesthetic and didn't have the wherewithal (because you were in pain!) to tell him.
Local hospitals and clinics are doing an OK job getting an electronic version of what used to be all paper records installed in their offices. But with all the different Health IT (HIT) vendors out there helping this process along, somebody's gotta work on getting them connected. That's what RHIOs are for. Start small at the local to state level and work your way up to a National Health Information Network (NHIN). That's the basic idea.
I'm in DC for a State RHIO Consensus conference hoping to get more info right from the source. Stay tuned!