The Internet's power to make something "go viral" has surpassed the phrase's original meaning.
Sneeze once, you might pass a virus to the person next to you. Post something online, the entire world might get infected.
Take the H1N1 vaccine: Last Thursday morning, the search term "H1N1 vaccine dangers" hit Google's top 10 searches.
A video of a cheerleader supposedly crippled after getting the flu vaccine received almost a million hits.
It's driving doctors crazy, as they insist the vaccine is safe and anti-vaccine preachers are plain wrong.
But the H1N1 story is evidence of a broader trend: The public's appetite for Internet health information has fundamentally altered the doctor-patient relationship.
Doctors are no longer perceived as the only authority on health information.
"People don't have that kind of patriarchal relationship with their physicians anymore," said Dr. Maxine Barish-Wreden, who heads Sutter's integrative medicine team. "They come in, and they're armed with some data already."
Almost all U.S. physicians said in a survey that at least some patients bring to appointments health information they found online, according to the Manhattan Research Group, a company that researches health care trends.