Here's Doximity in action, according to CEO Jeff Tangney.

"An emergency room doctor had a patient come in, took an X-ray and had some weird findings in the [patient's] intestine," recalled Tangney.

The doctor takes a picture of the X-ray with her smartphone and then posts it to the online network.

"There were a couple other physicians who chimed in and said, 'I've seen that before, that patient has little metal grill brush wires in their intestine,'" Tangney said.

The doctors swap messages on what to do and later decide to write a paper: metal shards are increasingly ending up in food, and grill brush standards need to be tougher to prevent it.

"Here's three people who would have never found each other in the past," Tangney said, "[who] have teamed up to write a paper that's been published about an area that probably needs some attention."

Information sharing is at the heart of Doximity. Tangney describes it as a online social network for physicians to collaborate, share lab reports and "securely communicate about things that matter." The goal is helping doctors provide better care.

The social network is free to the doctors. Tangney says the company is beginning to make money by charging lawyers, journalists and bankers for finding medical experts.

The California-based Doximity has already raised $28 million in venture capital.

More than 20,000 secure messages are sent across the network every day, according to Tangney. The network has over 100,000 verified doctors, many of whom compare notes on real medical records.

Sharing medical information over the internet has long been a challenge, according to Brian McGowan, a Blue Bell, Pa.-based health-care technology consultant.

Still, McGowan says doctors often need a network they can reach out to — beyond textbooks or colleagues down the hall.

"Doximity's trying to solve that problem by building consult networks that are broader than geography and broader than institutions, but are really based on individual expertise," McGowan said.

Complying with privacy laws is the main challenge, something that Doximity tackles with encryption software.

With studies showing that more doctors are using social media for professional development, Doximity hopes to become a force in the booming world of health IT.