Calling Dr. App. Calling Dr. App. Dr. Paul Friedman's late-night activities have people all over the world sending photos with silly messages to each other on their iPhones.

"I didn't really have a hobby. I don't garden or anything," the Mayo Clinic cardiologist said.  Then he bought an iPhone.

Soon Friedman, who was an electrical engineering major as an undergrad, became fascinated with the whole trend of small software programs or applications for the phone.

Post-Bulletin, by Jeff Kiger, 2/8/2010

Tags: Cardiology, Dr. Paul Friedman, iPhone app, Social Media