Is this a vanity service for wealthy hypochondriacs, or a harbinger of a coming revolution in health-care delivery? Possibly both. If some basic needs were addressed remotely, doctors could focus on more dire cases during their busy office hours. Patients could ask simple questions without needing to take an afternoon off work for an office visit. As of last year, only 12 percent of Americans had ever texted or e-mailed with a doctor, according to a survey conducted for The Atlantic. But about a third of people under 30 were open to having their primary communication with their doctors be online.

HealthTap is not, at least for now, trying to take over for anyone’s doctor. It is instead trying to supplement standard primary care. Specifically, it is trying to sell you on the idea of not ever having to wait for health-care advice. Upon hearing the story of an untimely fall from a horse or seeing a photo of a child’s post-water-park rash, the doctor on call might tell you to sit tight, or make an appointment to see someone in person, or run to the ER.

Doctors on HealthTap are paid for the time they spend conducting one-on-one consultations with patients, but they aren’t paid for answering questions submitted by anonymous users via the Web site. Why do they do it? “I think doctors are great people, in general,” Gutman told me. Being a doctor, I found that explanation reassuring. But physicians also participate in HealthTap for reasons not unlike the ones that motivate restaurants to post professional photos on Yelp and the CIA to join Twitter: they want to gain credibility and construct the dreaded but increasingly necessary online presence. Online presence is mentioned nowhere in the Hippocratic oath. But it can, Gutman says, help doctors “build a name and get speaking engagements, or just advance their careers.”

One doctor with an enviable online presence is Keegan Duchicela. HealthTap’s doctor-rating system gives him five out of five stars; he is also ranked first among HealthTap doctors nationwide for his knowledge of “insurance” and third for “abscessed tooth.” His profile boasts that his answers have been corroborated by other doctors 5,803 times, that patients have given him “thanks” 12,555 times, and that he has saved 25 users’ lives. (Whenever a doctor answers a question via the service, a pop-up box asks the patient whether the answer helped him, made him feel good, or saved his life. The number of “lives saved” by a given doctor indicates the number of people who checked that box. By this curious logic, HealthTap figures that its doctors have collectively saved 16,336 lives.)

On the basis of all this information, if you were in search of a family-medicine physician in Northern California, you might well seek out Duchicela, who practices in the Bay Area and teaches doctors-in-training at a Stanford-affiliated residency program. Especially in the tech-obsessed South Bay, Duchicela says, if a doctor doesn’t have an online presence, “patients think, Are you still using leeches?”