From top-dog Sermo to upstarts like Ozmosis.com and iMedExchange.com, the number of networking sites dedicated to physicians have proliferated recently.

After examining a woman suffering from severe pelvic pain and heavy bleeding, Danine Rydland, MD, knew she needed a drug that would suppress the patient's menstruation in preparation for her hysterectomy.

But the West Virginia ob/gyn didn't know exactly what to prescribe. At first, she thought birth-control pills were the answer, but she wavered after considering a host of complicating factors: The patient was a smoker over 35, suffered from a history of heart problems, and had pelvic surgery as a child.

Unsure of how to proceed, Rydland requested permission from the patient to post a description of the condition and history on http://www.Sermo.com, a social networking Web site for physicians. The patient consented, and a lively discussion ensued: In the days that followed, more than two dozen posts addressed Rydland's query.

A self-described Sermo addict, Rydland, 53, spends about two hours on the site each weekday and six hours over the weekend. "I like the community of doctors," she says. "I have made cyber-friends. They understand my problems and share my triumphs."

Judging by the number of similar sites popping up, an increasing number of doctors share Rydland's view.

At first considered little more than a refuge for teenagers discussing indie bands and cheerleaders, social networking sites have exploded beyond the bounds of MySpace and Facebook. From top-dog Sermo to upstarts like http://www.Ozmosis.com and http://www.iMedExchange.com, the number of networking sites dedicated to physicians has proliferated in the past year, offering opportunities to share advice on clinical situations, practice management-even what wine goes best with grilled salmon. And it's not just young doctors getting involved; the average age of Sermo members is 49.

But not all physicians are sold on social networking. Critics cite concerns over doctor-patient privacy, usefulness of shared information, and the looming specter of malpractice implications. What's more, some argue that Sermo, in particular, exploits its members by selling access to investment firms and other outside groups to observe physician interactions. Controversy may be brewing three years into the era of online physician networking, but the trend shows no signs of slowing.

A NEW KIND OF DOCTORS' LOUNGE

Daniel Palestrant, MD, was a surgical resident in the Boston area when the banter inside his hospital's physician lounge sparked his imagination.

He noticed that doctors learned a lot from informally chatting with colleagues, but they had no means of sharing, comparing, or evaluating those insights with members of the wider medical community. In 2006, Palestrant launched Sermo, named after the Latin word for "speech," with the vision of forging a platform for physician communication and collaboration.

Thus far, finances have not been a problem: Legg Mason Capital Management, a blue-chip private equity firm that is one of Sermo's major investors, has already poured some $40 million into the company, says Adam Sharp, MD, Sermo's chief medical officer and one of its first employees.

"The greatest unknown was: Would physicians buy in?" Sharp says.

More than 105,000 Sermo members have answered resoundingly. Enrollment has more than doubled from a year ago, and the site is adding new members at a rate of more than 1,000 a week, according to a spokeswoman.

"There are times many of us feel like we're on an island," says Baltimore ob/gyn Christos Ballas, MD, who opened his Sermo account in 2007, after reading about it in The Wall Street Journal. "[Sermo] makes me more comfortable knowing I'm not alone. I felt like I had immediate company with people in my own shoes."

Similar to MySpace and Facebook, Sermo contains profile pages that allow users to list their professional backgrounds, post blog entries about anything from clinical problems to vacation destinations, and use the site's self-contained e-mail program for personal, out-of-public-view communication between members.

"The unique thing is that you've got people from every specialty," says Elizabeth Pector, MD, a family physician from Naperville, Illinois, and an avid Sermo surfer. "You get an idea of what challenges psychiatrists, pediatricians, and oncologists are facing on a day-to-day basis, some sense of how they think, and what evidence they're taking into account when deciding on a treatment regimen."

Once, Pector posted a picture of her own swollen, aching wrist and asked for feedback on what the problem could be. Numerous diagnoses came in, ranging from arthritis to psoriasis to trauma. But after visiting a hand specialist, Pector learned the ultimate cause of her inflammation: "Two hours a day of clicking on a mouse," she says.