Before people hit the doctor's office, they tend to hit up Google. Though it's good to do research, a typical search for "how to soothe a headache" can lead to bogus tips and pseudoscience. The renowned Mayo Clinic's website keeps its tips legitimate, combining ease of use with sound medical advice. The site offers an encyclopedic index of diseases and a symptom checker to see what that forehead pain could mean. With an editorial staff full of M.D.s, you'll be sure to get your information from expert sources, though nothing can replace an actual doctor.